Add observers for DIP scale change.

content/browser/android/content_view_core_impl.h

Index: content/browser/android/content_view_core_impl.h
diff --git a/content/browser/android/content_view_core_impl.h b/content/browser/android/content_view_core_impl.h
index 387d4a5cc26697eaa23a9dd7e73aefed84a2bda7..ad4af26a2e2403b5fae4d7c0efec701899ad129c 100644
--- a/content/browser/android/content_view_core_impl.h
+++ b/content/browser/android/content_view_core_impl.h
@@ -224,6 +224,11 @@ class ContentViewCoreImpl : public ContentViewCore,
                 const base::android::JavaParamRef<jobject>& obj,
                 jboolean focused);
 
+  void SetDIPScale(JNIEnv* env,
+                   const base::android::JavaParamRef<jobject>& obj,
+                   jfloat dipScale,
+                   jboolean forceLayout);
+
   jint GetBackgroundColor(JNIEnv* env, jobject obj);
   void SetAllowJavascriptInterfacesInspection(
       JNIEnv* env,
@@ -383,6 +388,7 @@ class ContentViewCoreImpl : public ContentViewCore,
   float GetTopControlsHeightDip() const;
   float GetBottomControlsHeightDip() const;
 
+  void ForceLayout();

[boliu, 2016/10/18 00:26:25]

private?

[Tima Vaisburd, 2016/10/19 01:15:54]

Thank you. Done.

   void MoveRangeSelectionExtent(const gfx::PointF& extent);
 
   void SelectBetweenCoordinates(const gfx::PointF& base,
@@ -453,7 +459,7 @@ class ContentViewCoreImpl : public ContentViewCore,
   float page_scale_;
 
   // Device scale factor.
-  const float dpi_scale_;
+  float dpi_scale_;
 
   // Observer to notify of lifecyle changes.
   base::ObserverList<ContentViewCoreImplObserver> observer_list_;