skia: Use discardable memory for scaled image cache.

content/renderer/render_thread_impl.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/renderer/render_thread_impl.h"
 
 #include <algorithm>
 #include <limits>
 #include <map>
 #include <vector>
 
 #include "base/allocator/allocator_extension.h"
 #include "base/command_line.h"
 #include "base/debug/trace_event.h"
 #include "base/lazy_instance.h"
 #include "base/logging.h"
 #include "base/memory/discardable_memory.h"
 #include "base/memory/shared_memory.h"
 #include "base/metrics/field_trial.h"
 #include "base/metrics/histogram.h"
 #include "base/metrics/stats_table.h"
 #include "base/path_service.h"
 #include "base/strings/string16.h"
 #include "base/strings/string_tokenizer.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/threading/thread_local.h"
 #include "base/threading/thread_restrictions.h"
 #include "base/values.h"
+#include "cc/base/switches.h"
 #include "content/child/appcache/appcache_dispatcher.h"
 #include "content/child/appcache/appcache_frontend_impl.h"
 #include "content/child/child_histogram_message_filter.h"
 #include "content/child/db_message_filter.h"
 #include "content/child/indexed_db/indexed_db_dispatcher.h"
 #include "content/child/indexed_db/indexed_db_message_filter.h"
 #include "content/child/npapi/npobject_util.h"
 #include "content/child/plugin_messages.h"
 #include "content/child/resource_dispatcher.h"
 #include "content/child/runtime_features.h"
@@ skipping 673 matching lines @@
 
   FOR_EACH_OBSERVER(RenderProcessObserver, observers_, WebKitInitialized());
 
   devtools_agent_message_filter_ = new DevToolsAgentFilter();
   AddFilter(devtools_agent_message_filter_.get());
 
   if (GetContentClient()->renderer()->RunIdleHandlerWhenWidgetsHidden())
     ScheduleIdleHandler(kLongIdleHandlerDelayMs);
 
   webkit::SetSharedMemoryAllocationFunction(AllocateSharedMemoryFunction);
+
+  // Limit use of the scaled image cache to when deferred image decoding
+  // is enabled.
+  // TODO(reveman): Allow use of this cache on Android once
+  // SkDiscardablePixelRef is used for decoded images. crbug.com/330041
+  bool use_skia_scaled_image_cache = false;
+#if !defined(OS_ANDROID)
+  use_skia_scaled_image_cache =
+      command_line.HasSwitch(switches::kEnableDeferredImageDecoding) ||
+      cc::switches::IsImplSidePaintingEnabled();
+#endif
+  if (!use_skia_scaled_image_cache)
+    SkGraphics::SetImageCacheByteLimit(0u);
 }
 
 void RenderThreadImpl::RegisterSchemes() {
   // swappedout: pages should not be accessible, and should also
   // be treated as empty documents that can commit synchronously.
   WebString swappedout_scheme(base::ASCIIToUTF16(kSwappedOutScheme));
   WebSecurityPolicy::registerURLSchemeAsDisplayIsolated(swappedout_scheme);
   WebSecurityPolicy::registerURLSchemeAsEmptyDocument(swappedout_scheme);
 }
 
@@ skipping 622 matching lines @@
   if (!gamepad_shared_memory_reader_)
     gamepad_shared_memory_reader_.reset(new GamepadSharedMemoryReader);
   gamepad_shared_memory_reader_->SampleGamepads(*data);
 }
 
 base::ProcessId RenderThreadImpl::renderer_process_id() const {
   return renderer_process_id_;
 }
 
 }  // namespace content