Add a DiscardableMemoryShmemeAllocator.

mojo/services/html_viewer/html_viewer.cc

Index: mojo/services/html_viewer/html_viewer.cc
diff --git a/mojo/services/html_viewer/html_viewer.cc b/mojo/services/html_viewer/html_viewer.cc
index 8c71a9f3ab55ab08188141b4208174ff49dc615b..5c737df045b78ba8bd4db923ae75bd6be96f0eeb 100644
--- a/mojo/services/html_viewer/html_viewer.cc
+++ b/mojo/services/html_viewer/html_viewer.cc
@@ -11,6 +11,7 @@
 #include "gin/public/isolate_holder.h"
 #include "mojo/application/application_runner_chromium.h"
 #include "mojo/services/html_viewer/html_document.h"
+#include "mojo/services/html_viewer/html_viewer_discardable_memory_shmem_allocator.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"
@@ -168,6 +169,9 @@ class HTMLViewer : public mojo::ApplicationDelegate,
  private:
   // Overridden from ApplicationDelegate:
   void Initialize(mojo::ApplicationImpl* app) override {
+    base::DiscardableMemoryShmemAllocator::SetInstance(
+        &discardable_memory_allocator_);
+
     blink_platform_.reset(new MojoBlinkPlatformImpl(app));
 #if defined(V8_USE_EXTERNAL_STARTUP_DATA)
     // Note: this requires file system access.
@@ -234,6 +238,11 @@ class HTMLViewer : public mojo::ApplicationDelegate,
         &request);
   }
 
+  // TODO(erg): Skia requires that we have one of these. However, all the

[jamesr, 2015/03/16 23:47:25]

what's the action item of the TODO here?

+  // fancy, non-testing versions of this look like they won't work out of the
+  // box with mojo.
+  HtmlViewerDiscardableMemoryShmemAllocator discardable_memory_allocator_;
+
   scoped_ptr<MojoBlinkPlatformImpl> blink_platform_;
   base::Thread compositor_thread_;
   scoped_ptr<WebMediaPlayerFactory> web_media_player_factory_;