diff --git a/libs/ui/GraphicBufferAllocator.cpp b/libs/ui/GraphicBufferAllocator.cpp
index eaba1ed..a2f1783 100644
--- a/libs/ui/GraphicBufferAllocator.cpp
+++ b/libs/ui/GraphicBufferAllocator.cpp
@@ -24,9 +24,9 @@
 
 #include <grallocusage/GrallocUsageConversion.h>
 
+#include <android-base/stringprintf.h>
 #include <log/log.h>
 #include <utils/Singleton.h>
-#include <utils/String8.h>
 #include <utils/Trace.h>
 
 #include <ui/Gralloc2.h>
@@ -35,6 +35,8 @@
 namespace android {
 // ---------------------------------------------------------------------------
 
+using base::StringAppendF;
+
 ANDROID_SINGLETON_STATIC_INSTANCE( GraphicBufferAllocator )
 
 Mutex GraphicBufferAllocator::sLock;
@@ -50,46 +52,37 @@
 
 GraphicBufferAllocator::~GraphicBufferAllocator() {}
 
-void GraphicBufferAllocator::dump(String8& result) const
-{
+void GraphicBufferAllocator::dump(std::string& result) const {
     Mutex::Autolock _l(sLock);
     KeyedVector<buffer_handle_t, alloc_rec_t>& list(sAllocList);
     size_t total = 0;
-    const size_t SIZE = 4096;
-    char buffer[SIZE];
-    snprintf(buffer, SIZE, "Allocated buffers:\n");
-    result.append(buffer);
+    result.append("Allocated buffers:\n");
     const size_t c = list.size();
     for (size_t i=0 ; i<c ; i++) {
         const alloc_rec_t& rec(list.valueAt(i));
         if (rec.size) {
-            snprintf(buffer, SIZE, "%10p: %7.2f KiB | %4u (%4u) x %4u | %4u | %8X | 0x%" PRIx64
-                    " | %s\n",
-                    list.keyAt(i), rec.size/1024.0,
-                    rec.width, rec.stride, rec.height, rec.layerCount, rec.format,
-                    rec.usage, rec.requestorName.c_str());
+            StringAppendF(&result,
+                          "%10p: %7.2f KiB | %4u (%4u) x %4u | %4u | %8X | 0x%" PRIx64 " | %s\n",
+                          list.keyAt(i), rec.size / 1024.0, rec.width, rec.stride, rec.height,
+                          rec.layerCount, rec.format, rec.usage, rec.requestorName.c_str());
         } else {
-            snprintf(buffer, SIZE, "%10p: unknown     | %4u (%4u) x %4u | %4u | %8X | 0x%" PRIx64
-                    " | %s\n",
-                    list.keyAt(i),
-                    rec.width, rec.stride, rec.height, rec.layerCount, rec.format,
-                    rec.usage, rec.requestorName.c_str());
+            StringAppendF(&result,
+                          "%10p: unknown     | %4u (%4u) x %4u | %4u | %8X | 0x%" PRIx64 " | %s\n",
+                          list.keyAt(i), rec.width, rec.stride, rec.height, rec.layerCount,
+                          rec.format, rec.usage, rec.requestorName.c_str());
         }
-        result.append(buffer);
         total += rec.size;
     }
-    snprintf(buffer, SIZE, "Total allocated (estimate): %.2f KB\n", total/1024.0);
-    result.append(buffer);
+    StringAppendF(&result, "Total allocated (estimate): %.2f KB\n", total / 1024.0);
 
-    std::string deviceDump = mAllocator->dumpDebugInfo();
-    result.append(deviceDump.c_str(), deviceDump.size());
+    result.append(mAllocator->dumpDebugInfo());
 }
 
 void GraphicBufferAllocator::dumpToSystemLog()
 {
-    String8 s;
+    std::string s;
     GraphicBufferAllocator::getInstance().dump(s);
-    ALOGD("%s", s.string());
+    ALOGD("%s", s.c_str());
 }
 
 status_t GraphicBufferAllocator::allocate(uint32_t width, uint32_t height,
diff --git a/libs/ui/Region.cpp b/libs/ui/Region.cpp
index 618c7d6..3bd3748 100644
--- a/libs/ui/Region.cpp
+++ b/libs/ui/Region.cpp
@@ -19,8 +19,9 @@
 #include <inttypes.h>
 #include <limits.h>
 
+#include <android-base/stringprintf.h>
+
 #include <utils/Log.h>
-#include <utils/String8.h>
 #include <utils/CallStack.h>
 
 #include <ui/Rect.h>
@@ -41,6 +42,8 @@
 namespace android {
 // ----------------------------------------------------------------------------
 
+using base::StringAppendF;
+
 enum {
     op_nand = region_operator<Rect>::op_nand,
     op_and  = region_operator<Rect>::op_and,
@@ -868,16 +871,14 @@
 
 // ----------------------------------------------------------------------------
 
-void Region::dump(String8& out, const char* what, uint32_t /* flags */) const
-{
+void Region::dump(std::string& out, const char* what, uint32_t /* flags */) const {
     const_iterator head = begin();
     const_iterator const tail = end();
 
-    out.appendFormat("  Region %s (this=%p, count=%" PRIdPTR ")\n",
-            what, this, tail - head);
+    StringAppendF(&out, "  Region %s (this=%p, count=%" PRIdPTR ")\n", what, this, tail - head);
     while (head != tail) {
-        out.appendFormat("    [%3d, %3d, %3d, %3d]\n", head->left, head->top,
-                head->right, head->bottom);
+        StringAppendF(&out, "    [%3d, %3d, %3d, %3d]\n", head->left, head->top, head->right,
+                      head->bottom);
         ++head;
     }
 }
diff --git a/libs/ui/UiConfig.cpp b/libs/ui/UiConfig.cpp
index 7730690..0ac863d 100644
--- a/libs/ui/UiConfig.cpp
+++ b/libs/ui/UiConfig.cpp
@@ -18,8 +18,7 @@
 
 namespace android {
 
-void appendUiConfigString(String8& configStr)
-{
+void appendUiConfigString(std::string& configStr) {
     static const char* config =
             " [libui]";
     configStr.append(config);
diff --git a/libs/ui/include/ui/GraphicBufferAllocator.h b/libs/ui/include/ui/GraphicBufferAllocator.h
index 14a865e..7e2b230 100644
--- a/libs/ui/include/ui/GraphicBufferAllocator.h
+++ b/libs/ui/include/ui/GraphicBufferAllocator.h
@@ -39,7 +39,6 @@
 }
 
 class GraphicBufferMapper;
-class String8;
 
 class GraphicBufferAllocator : public Singleton<GraphicBufferAllocator>
 {
@@ -53,7 +52,7 @@
 
     status_t free(buffer_handle_t handle);
 
-    void dump(String8& res) const;
+    void dump(std::string& res) const;
     static void dumpToSystemLog();
 
 private:
diff --git a/libs/ui/include/ui/Region.h b/libs/ui/include/ui/Region.h
index 0a09960..79642ae 100644
--- a/libs/ui/include/ui/Region.h
+++ b/libs/ui/include/ui/Region.h
@@ -27,12 +27,11 @@
 
 #include <android-base/macros.h>
 
+#include <string>
+
 namespace android {
 // ---------------------------------------------------------------------------
 
-class String8;
-
-// ---------------------------------------------------------------------------
 class Region : public LightFlattenable<Region>
 {
 public:
@@ -144,8 +143,8 @@
             status_t    flatten(void* buffer, size_t size) const;
             status_t    unflatten(void const* buffer, size_t size);
 
-    void        dump(String8& out, const char* what, uint32_t flags=0) const;
-    void        dump(const char* what, uint32_t flags=0) const;
+            void        dump(std::string& out, const char* what, uint32_t flags=0) const;
+            void        dump(const char* what, uint32_t flags=0) const;
 
 private:
     class rasterizer;
diff --git a/libs/ui/include/ui/UiConfig.h b/libs/ui/include/ui/UiConfig.h
index fcf8ed5..d1d6014 100644
--- a/libs/ui/include/ui/UiConfig.h
+++ b/libs/ui/include/ui/UiConfig.h
@@ -17,12 +17,12 @@
 #ifndef ANDROID_UI_CONFIG_H
 #define ANDROID_UI_CONFIG_H
 
-#include <utils/String8.h>
+#include <string>
 
 namespace android {
 
 // Append the libui configuration details to configStr.
-void appendUiConfigString(String8& configStr);
+void appendUiConfigString(std::string& configStr);
 
 }; // namespace android