[Slimming Paint] Paint the inspector overlay with GraphicsLayer DisplayList.

Source/web/WebPageOverlay.cpp

Index: Source/web/WebPageOverlay.cpp
diff --git a/Source/web/WebPageOverlay.cpp b/Source/web/WebPageOverlay.cpp
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+++ b/Source/web/WebPageOverlay.cpp
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+// Copyright 2015 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 "config.h"
+#include "public/web/WebPageOverlay.h"
+
+#include "public/platform/WebSize.h"
+#include "public/web/WebGraphicsContext.h"
+#include "third_party/skia/include/core/SkCanvas.h"
+#include "third_party/skia/include/core/SkRect.h"
+
+namespace blink {
+
+void WebPageOverlay::paintPageOverlay(WebGraphicsContext* context, const WebSize& webViewSize)
+{
+    WebFloatRect rect(0, 0, webViewSize.width, webViewSize.height);
+    WebCanvas* canvas = context->beginDrawing(rect);
+    int saveCount = canvas->save();
+    canvas->clipRect(SkRect::MakeWH(webViewSize.width, webViewSize.height));
+    paintPageOverlay(canvas);
+    canvas->restoreToCount(saveCount);
+    context->endDrawing();
+}
+
+void WebPageOverlay::paintPageOverlay(WebCanvas*)
+{
+}
+
+} // namespace blink