Add a DiscardableMemoryShmemeAllocator.

mojo/services/html_viewer/html_viewer.cc

 // Copyright 2014 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 "base/command_line.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/message_loop/message_loop.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/threading/thread.h"
 #include "gin/public/isolate_holder.h"
 #include "mojo/application/application_runner_chromium.h"
+#include "mojo/services/html_viewer/discardable_memory_allocator.h"
 #include "mojo/services/html_viewer/html_document.h"
 #include "mojo/services/html_viewer/mojo_blink_platform_impl.h"
 #include "mojo/services/html_viewer/webmediaplayer_factory.h"
 #include "mojo/services/network/public/interfaces/network_service.mojom.h"
 #include "third_party/WebKit/public/web/WebKit.h"
 #include "third_party/WebKit/public/web/WebRuntimeFeatures.h"
 #include "third_party/mojo/src/mojo/public/c/system/main.h"
 #include "third_party/mojo/src/mojo/public/cpp/application/application_connection.h"
 #include "third_party/mojo/src/mojo/public/cpp/application/application_delegate.h"
 #include "third_party/mojo/src/mojo/public/cpp/application/application_impl.h"
@@ skipping 29 matching lines @@
 // Enable MediaRenderer in media pipeline instead of using the internal
 // media::Renderer implementation.
 const char kEnableMojoMediaRenderer[] = "enable-mojo-media-renderer";
 
 // Disables support for (unprefixed) Encrypted Media Extensions.
 const char kDisableEncryptedMedia[] = "disable-encrypted-media";
 
 // Prevents creation of any output surface.
 const char kIsHeadless[] = "is-headless";
 
+size_t kDesiredMaxMemory = 20 * 1024 * 1024;
+
 class HTMLViewer;
 
 class HTMLViewerApplication : public mojo::Application {
  public:
   HTMLViewerApplication(InterfaceRequest<Application> request,
                         URLResponsePtr response,
                         scoped_refptr<base::MessageLoopProxy> compositor_thread,
                         WebMediaPlayerFactory* web_media_player_factory,
                         bool is_headless)
       : url_(response->url),
@@ skipping 82 matching lines @@
   scoped_refptr<base::MessageLoopProxy> compositor_thread_;
   WebMediaPlayerFactory* web_media_player_factory_;
   bool is_headless_;
 
   DISALLOW_COPY_AND_ASSIGN(ContentHandlerImpl);
 };
 
 class HTMLViewer : public mojo::ApplicationDelegate,
                    public mojo::InterfaceFactory<ContentHandler> {
  public:
-  HTMLViewer() : compositor_thread_("compositor thread") {}
+  HTMLViewer()
+      : discardable_memory_allocator_(kDesiredMaxMemory),
+        compositor_thread_("compositor thread") {}
 
   ~HTMLViewer() override { blink::shutdown(); }
 
  private:
   // Overridden from ApplicationDelegate:
   void Initialize(mojo::ApplicationImpl* app) override {
+    base::DiscardableMemoryAllocator::SetInstance(
+        &discardable_memory_allocator_);
+
     blink_platform_.reset(new MojoBlinkPlatformImpl(app));
 #if defined(V8_USE_EXTERNAL_STARTUP_DATA)
     // Note: this requires file system access.
     gin::IsolateHolder::LoadV8Snapshot();
 #endif
     blink::initialize(blink_platform_.get());
     base::i18n::InitializeICU();
 
     ui::RegisterPathProvider();
 
@@ skipping 46 matching lines @@
 
   // Overridden from InterfaceFactory<ContentHandler>
   void Create(ApplicationConnection* connection,
               mojo::InterfaceRequest<ContentHandler> request) override {
     BindToRequest(
         new ContentHandlerImpl(compositor_thread_.message_loop_proxy(),
                                web_media_player_factory_.get(), is_headless_),
         &request);
   }
 
+  // Skia requires that we have one of these. Unlike the one used in chrome,
+  // this doesn't use purgable shared memory. Instead, it tries to free the
+  // oldest unlocked chunks on allocation.
+  //
+  // TODO(erg): In the long run, delete this allocator and get the real shared
+  // memory based purging allocator working here.
+  DiscardableMemoryAllocator discardable_memory_allocator_;
+
   scoped_ptr<MojoBlinkPlatformImpl> blink_platform_;
   base::Thread compositor_thread_;
   scoped_ptr<WebMediaPlayerFactory> web_media_player_factory_;
   // Set if the content will never be displayed.
   bool is_headless_;
 
   DISALLOW_COPY_AND_ASSIGN(HTMLViewer);
 };
 
 }  // namespace html_viewer
 
 MojoResult MojoMain(MojoHandle shell_handle) {
   mojo::ApplicationRunnerChromium runner(new html_viewer::HTMLViewer);
   return runner.Run(shell_handle);
 }