Update bench pictures to time image decode & upload costs

tools/PictureRenderer.cpp

Index: tools/PictureRenderer.cpp
===================================================================
--- tools/PictureRenderer.cpp	(revision 12709)
+++ tools/PictureRenderer.cpp	(working copy)
@@ -12,6 +12,7 @@
 #include "SkCanvas.h"
 #include "SkData.h"
 #include "SkDevice.h"
+#include "SkDiscardableMemoryPool.h"
 #include "SkGPipe.h"
 #if SK_SUPPORT_GPU
 #include "gl/GrGLDefines.h"
@@ -34,6 +35,15 @@
 #include "SkThreadUtils.h"
 #include "SkTypes.h"
 
+class SkTools_PictureRenderer {
+private:
+    static void PurgeAllUnlockedTextures(GrContext* context) {
+        context->purgeAllUnlocked();
+    }
+
+    friend class sk_tools::PictureRenderer;
+};
+
 namespace sk_tools {
 
 enum {
@@ -240,6 +250,25 @@
 #endif
 }
 
+void PictureRenderer::purgeTextures() {
+    SkDiscardableMemoryPool* pool = SkGetGlobalDiscardableMemoryPool();
+
+    pool->dumpPool();
+
+#if SK_SUPPORT_GPU
+    SkGLContextHelper* glContext = this->getGLContext();
+    if (NULL == glContext) {
+        SkASSERT(kBitmap_DeviceType == fDeviceType);
+        return;
+    }
+
+    // resetState should've already done this
+    fGrContext->flush();
+
+    SkTools_PictureRenderer::PurgeAllUnlockedTextures(fGrContext);
+#endif
+}
+
 uint32_t PictureRenderer::recordFlags() {
     return ((kNone_BBoxHierarchyType == fBBoxHierarchyType) ? 0 :
         SkPicture::kOptimizeForClippedPlayback_RecordingFlag) |