Merged op dispatch in OpReorderer

bug:22480459

Also switches std::functions to function pointers on OpReorderer, and
switches AssetAtlas' entry getter methods to using pixelRef pointers,
so it's clear they're the keys.

Change-Id: I3040ce5ff4e178a8364e0fd7ab0876ada7d4de05
diff --git a/libs/hwui/TextureCache.cpp b/libs/hwui/TextureCache.cpp
index a6c72a3..21901cf 100644
--- a/libs/hwui/TextureCache.cpp
+++ b/libs/hwui/TextureCache.cpp
@@ -138,7 +138,7 @@
 // in the cache (and is thus added to the cache)
 Texture* TextureCache::getCachedTexture(const SkBitmap* bitmap, AtlasUsageType atlasUsageType) {
     if (CC_LIKELY(mAssetAtlas != nullptr) && atlasUsageType == AtlasUsageType::Use) {
-        AssetAtlas::Entry* entry = mAssetAtlas->getEntry(bitmap);
+        AssetAtlas::Entry* entry = mAssetAtlas->getEntry(bitmap->pixelRef());
         if (CC_UNLIKELY(entry)) {
             return entry->texture;
         }