Expose functionality to purge the GPU texture cache while running SampleApp.

Press 'p' to purge the cache.  A summary of the number of bytes of video memory
released is output to the command prompt.
Review URL: https://codereview.appspot.com/5587045

git-svn-id: http://skia.googlecode.com/svn/trunk@3097 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/gpu/GrContext.cpp b/src/gpu/GrContext.cpp
index 2132ed6..975f6d0 100644
--- a/src/gpu/GrContext.cpp
+++ b/src/gpu/GrContext.cpp
@@ -115,6 +115,10 @@
     GrSafeSetNull(fPathRendererChain);
 }
 
+size_t GrContext::getGpuTextureCacheBytes() const {
+  return fTextureCache->getCachedResourceBytes();
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 
 int GrContext::PaintStageVertexLayoutBits(
diff --git a/src/gpu/GrResourceCache.h b/src/gpu/GrResourceCache.h
index e21c605..f86fcd2 100644
--- a/src/gpu/GrResourceCache.h
+++ b/src/gpu/GrResourceCache.h
@@ -209,6 +209,11 @@
     void setLimits(int maxResource, size_t maxResourceBytes);
 
     /**
+     * Returns the number of bytes consumed by cached resources.
+     */
+    size_t getCachedResourceBytes() const { return fEntryBytes; }
+
+    /**
      * Controls whether locks should be nestable or not.
      */
     enum LockType {
@@ -315,4 +320,3 @@
 #endif
 
 #endif
-