Add BlimpView to a Chrome tab when Blimp is enabled.

blimp/client/core/contents/blimp_contents_impl.h

Index: blimp/client/core/contents/blimp_contents_impl.h
diff --git a/blimp/client/core/contents/blimp_contents_impl.h b/blimp/client/core/contents/blimp_contents_impl.h
index e8b4a6bde29391dca219c174a8bccacd553aaa5b..dee1c3c364d905233a5baad227ed50e4495506ee 100644
--- a/blimp/client/core/contents/blimp_contents_impl.h
+++ b/blimp/client/core/contents/blimp_contents_impl.h
@@ -11,6 +11,7 @@
 #include "blimp/client/core/contents/blimp_navigation_controller_impl.h"
 #include "blimp/client/public/contents/blimp_contents.h"
 #include "ui/gfx/geometry/size.h"
+#include "ui/gfx/native_widget_types.h"
 #include "url/gurl.h"
 
 #if defined(OS_ANDROID)
@@ -34,7 +35,9 @@ class BlimpContentsImpl : public BlimpContents,
                           public BlimpNavigationControllerDelegate {
  public:
   // Ownership of the features remains with the caller.
+  // |window| must be the platform specific window that this will be shown in.
   explicit BlimpContentsImpl(int id,
+                             gfx::NativeWindow window,
                              ImeFeature* ime_feature,
                              NavigationFeature* navigation_feature,
                              TabControlFeature* tab_control_feature);
@@ -50,6 +53,9 @@ class BlimpContentsImpl : public BlimpContents,
   void AddObserver(BlimpContentsObserver* observer) override;
   void RemoveObserver(BlimpContentsObserver* observer) override;
 
+  // Returns the platform specific window that this BlimpContents is showed in.
+  gfx::NativeWindow GetNativeWindow();
+
   // Check if some observer is in the observer list.
   bool HasObserver(BlimpContentsObserver* observer);
 
@@ -73,6 +79,9 @@ class BlimpContentsImpl : public BlimpContents,
   // BlimpContentsManager to control the life time of the its observer.
   int id_;
 
+  // The platform specific window that this BlimpContents is showed in.
+  gfx::NativeWindow window_;
+
   // The tab control feature through which the BlimpContentsImpl is able to
   // set size and scale.
   // TODO(mlliu): in the long term, we want to put size and scale in a different