Add a full Blimp integration test.

blimp/client/test/compositor/test_display_compositor.h

Index: blimp/client/test/compositor/test_display_compositor.h
diff --git a/blimp/client/test/compositor/test_display_compositor.h b/blimp/client/test/compositor/test_display_compositor.h
new file mode 100644
index 0000000000000000000000000000000000000000..5235c1ab86adb26208ea657a2bbb50074ec23e01
--- /dev/null
+++ b/blimp/client/test/compositor/test_display_compositor.h
@@ -0,0 +1,51 @@
+// Copyright 2016 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.
+
+#ifndef BLIMP_CLIENT_TEST_COMPOSITOR_TEST_DISPLAY_COMPOSITOR_H_
+#define BLIMP_CLIENT_TEST_COMPOSITOR_TEST_DISPLAY_COMPOSITOR_H_
+
+#include "base/callback.h"
+#include "base/macros.h"
+#include "blimp/client/support/compositor/display_compositor.h"
+
+class SkBitmap;
+
+namespace cc {
+class CopyOutputResult;
+}  // namespace cc
+
+namespace blimp {
+namespace client {
+class CompositorDependencies;
+
+// An implementation of the DisplayCompositor that supplies a ContextProvider
+// that is not backed by a platform specific widget.  It is not meant to be used
+// to actually display content.  It also provides a hook to get access to an
+// SkBitmap that represents the cc::Layer passed into |SetContentLayer|.
+class TestDisplayCompositor : public DisplayCompositor {
+ public:
+  struct CopyRequest {
+    CopyRequest();
+    ~CopyRequest();
+
+    base::WaitableEvent waiter;
+    std::unique_ptr<SkBitmap> result;
+  };
+
+  explicit TestDisplayCompositor(
+      CompositorDependencies* compositor_dependencies);
+  ~TestDisplayCompositor() override;
+
+  // Returns an SkBitmap that represents the cc::Layer hierarchy being drawn by
+  // this compositor.  This will block until the readback completes.
+  void GetBitmap(CopyRequest* request);

[Khushal, 2016/09/13 04:47:24]

I know you really wanted a sync call but I would say this half here, half there
WaitableEvent logic feels prone to errors later, might be cleaner to put it all
on the caller and make an async API here. Up to you though.

[David Trainor- moved to gerrit, 2016/09/13 06:18:05]

This is all gone.  Moved to BlimpContentsView like we discussed.  All async.

+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(TestDisplayCompositor);
+};
+
+}  // namespace client
+}  // namespace blimp
+
+#endif  // BLIMP_CLIENT_TEST_COMPOSITOR_TEST_DISPLAY_COMPOSITOR_H_