cc: Adding support for RGBA_4444 tile textures

cc/resources/tile_manager.cc

Index: cc/resources/tile_manager.cc
diff --git a/cc/resources/tile_manager.cc b/cc/resources/tile_manager.cc
index 3d1ce0be9867c876356d931dbf169aaddcef0005..fc05451b102b7be61d7f8252293917c242968626 100644
--- a/cc/resources/tile_manager.cc
+++ b/cc/resources/tile_manager.cc
@@ -103,6 +103,14 @@ inline ManagedTileBin BinFromTilePriority(const TilePriority& prio,
 // of time scheduling one enormous set of tasks.
 const size_t kMaxRasterTasks = 256u;
 
+// static
+cc::ResourceProvider::TextureFormat GetTextureFormat(
+    cc::ResourceProvider* provider,
+    bool use_rgba_4444_tiles) {
+  return use_rgba_4444_tiles ? cc::ResourceProvider::RGBA_4444 :
+      provider->best_texture_format();
+}
+
 }  // namespace
 
 RasterTaskCompletionStats::RasterTaskCompletionStats()
@@ -125,7 +133,8 @@ scoped_ptr<TileManager> TileManager::Create(
     size_t num_raster_threads,
     RenderingStatsInstrumentation* rendering_stats_instrumentation,
     bool use_map_image,
-    size_t max_transfer_buffer_usage_bytes) {
+    size_t max_transfer_buffer_usage_bytes,
+    bool use_rgba_4444_tiles) {
   return make_scoped_ptr(
       new TileManager(client,
                       resource_provider,
@@ -135,9 +144,13 @@ scoped_ptr<TileManager> TileManager::Create(
                       PixelBufferRasterWorkerPool::Create(
                           resource_provider,
                           num_raster_threads,
-                          max_transfer_buffer_usage_bytes),
+                          max_transfer_buffer_usage_bytes,
+                          GetTextureFormat(resource_provider,
+                                           use_rgba_4444_tiles)),
                       num_raster_threads,
-                      rendering_stats_instrumentation));
+                      rendering_stats_instrumentation,
+                      GetTextureFormat(resource_provider,
+                                       use_rgba_4444_tiles)));
 }
 
 TileManager::TileManager(
@@ -145,7 +158,8 @@ TileManager::TileManager(
     ResourceProvider* resource_provider,
     scoped_ptr<RasterWorkerPool> raster_worker_pool,
     size_t num_raster_threads,
-    RenderingStatsInstrumentation* rendering_stats_instrumentation)
+    RenderingStatsInstrumentation* rendering_stats_instrumentation,
+    ResourceProvider::TextureFormat texture_type)
     : client_(client),
       resource_pool_(ResourcePool::Create(resource_provider)),
       raster_worker_pool_(raster_worker_pool.Pass()),
@@ -156,7 +170,8 @@ TileManager::TileManager(
       resources_releasable_(0),
       ever_exceeded_memory_budget_(false),
       rendering_stats_instrumentation_(rendering_stats_instrumentation),
-      did_initialize_visible_tile_(false) {
+      did_initialize_visible_tile_(false),
+      texture_type_(texture_type) {
   raster_worker_pool_->SetClient(this);
 }
 
@@ -722,6 +737,7 @@ RasterWorkerPool::RasterTask TileManager::CreateRasterTask(Tile* tile) {
       resource_pool_->AcquireResource(
           tile->tile_size_.size(),
           raster_worker_pool_->GetResourceFormat());
+
   const Resource* const_resource = resource.get();
 
   // Create and queue all image decode tasks that this tile depends on.
@@ -765,7 +781,8 @@ RasterWorkerPool::RasterTask TileManager::CreateRasterTask(Tile* tile) {
                  tile->id(),
                  base::Passed(&resource),
                  mts.raster_mode),
-      &decode_tasks);
+      &decode_tasks,
+      texture_type_);
 }
 
 void TileManager::OnImageDecodeTaskCompleted(