Fix google-explicit-constructor warnings in libs/hwui.

* Add explicit keyword to conversion constructors,
  or add NOLINT for implicit converters.
Bug: 28341362
Test: build with WITH_TIDY=1

Change-Id: Id8ca42433a4fc3652e4cb13787c4cb169f20d9a9
diff --git a/libs/hwui/utils/FatVector.h b/libs/hwui/utils/FatVector.h
index 93d37c2..df8cb076 100644
--- a/libs/hwui/utils/FatVector.h
+++ b/libs/hwui/utils/FatVector.h
@@ -53,7 +53,7 @@
     typedef T value_type; // needed to implement std::allocator
     typedef T* pointer; // needed to implement std::allocator
 
-    InlineStdAllocator(Allocation& allocation)
+    explicit InlineStdAllocator(Allocation& allocation)
             : mAllocation(allocation) {}
     InlineStdAllocator(const InlineStdAllocator& other)
             : mAllocation(other.mAllocation) {}
@@ -93,7 +93,7 @@
         this->reserve(SIZE);
     }
 
-    FatVector(size_t capacity) : FatVector() {
+    explicit FatVector(size_t capacity) : FatVector() {
         this->resize(capacity);
     }