Make GrResourceCache dynamically change between LRU and random replacement strategies.

src/gpu/GrDrawingManager.cpp

Index: src/gpu/GrDrawingManager.cpp
diff --git a/src/gpu/GrDrawingManager.cpp b/src/gpu/GrDrawingManager.cpp
index 5e9b68d88f3b40ddb14866b0957b1149b255e6ca..75195670b2530744e73740fb9eb3ca3926667d16 100644
--- a/src/gpu/GrDrawingManager.cpp
+++ b/src/gpu/GrDrawingManager.cpp
@@ -129,10 +129,17 @@ void GrDrawingManager::internalFlush(GrResourceCache::FlushType type) {
 #endif
 
     fFlushState.reset();
-    // We always have to notify the cache when it requested a flush so it can reset its state.
-    if (flushed || type == GrResourceCache::FlushType::kCacheRequested) {
+    // Avoid notifying the cache about successive client flushes where no rendering occurred between
+    // them.
+    bool skipNotify = false;
+    if (!flushed) {
+        skipNotify = GrResourceCache::kExternal == fLastFlushType &&
+                     GrResourceCache::kExternal == type;
+    }
+    if (!skipNotify) {
         fContext->getResourceCache()->notifyFlushOccurred(type);
     }
+    fLastFlushType = type;
     fFlushing = false;
 }
 
@@ -145,6 +152,9 @@ void GrDrawingManager::prepareSurfaceForExternalIO(GrSurface* surface) {
 
     if (surface->surfacePriv().hasPendingIO()) {
         this->flush();
+    } else if (GrResourceCache::kExternal != fLastFlushType) {
+        fContext->getResourceCache()->notifyFlushOccurred(GrResourceCache::kExternal);
+        fLastFlushType = GrResourceCache::kExternal;
     }
 
     GrRenderTarget* rt = surface->asRenderTarget();