Add traces of the size of HWUI shader cache in RAM

When HWUI needs to either load a shader from or store one to persistent
storage, this means a new shader is in its temporary (RAM) cache. Keep
track of the number and include it in perfetto traces.

As long as we're modifying ::store, make it override the version with
the newer signature, since the old one is deprecated.

Bug: 231194869
Bug: 225211273
Test: manual

Change-Id: I36b7e018291c50ed315f534f15946047ca001300
diff --git a/libs/hwui/pipeline/skia/ShaderCache.h b/libs/hwui/pipeline/skia/ShaderCache.h
index 4dcc9fb..3e0fd51 100644
--- a/libs/hwui/pipeline/skia/ShaderCache.h
+++ b/libs/hwui/pipeline/skia/ShaderCache.h
@@ -73,7 +73,7 @@
      * "store" attempts to insert a new key/value blob pair into the cache.
      * This will be called by Skia after it compiled a new SKSL shader
      */
-    void store(const SkData& key, const SkData& data) override;
+    void store(const SkData& key, const SkData& data, const SkString& description) override;
 
     /**
      * "onVkFrameFlushed" tries to store Vulkan pipeline cache state.
@@ -210,6 +210,13 @@
      */
     static constexpr uint8_t sIDKey = 0;
 
+    /**
+     * Most of this class concerns persistent storage for shaders, but it's also
+     * interesting to keep track of how many shaders are stored in RAM. This
+     * class provides a convenient entry point for that.
+     */
+    int mNumShadersCachedInRam = 0;
+
     friend class ShaderCacheTestUtils;  // used for unit testing
 };