Add observers for DIP scale change.

content/browser/android/content_view_core_impl.cc

Index: content/browser/android/content_view_core_impl.cc
diff --git a/content/browser/android/content_view_core_impl.cc b/content/browser/android/content_view_core_impl.cc
index e627fcd7611712cccc0a78f09b97a433a233f072..cb5e74238d7442af4ce643c56f076240d6e19eea 100644
--- a/content/browser/android/content_view_core_impl.cc
+++ b/content/browser/android/content_view_core_impl.cc
@@ -884,6 +884,17 @@ void ContentViewCoreImpl::SetFocus(JNIEnv* env,
   SetFocusInternal(focused);
 }
 
+void ContentViewCoreImpl::SetDIPScale(JNIEnv* env,
+                                      const JavaParamRef<jobject>& obj,
+                                      jfloat dipScale) {
+  dpi_scale_ = dipScale;
+
+  // Force new layout.
+  RenderWidgetHostViewAndroid* view = GetRenderWidgetHostViewAndroid();
+  if (view)
+    view->WasResized();

[boliu, 2016/09/15 05:27:41]

don't duplicate code, factor out the current CVCI::WasResized method into a
helper method and call the helper instead

[Tima Vaisburd, 2016/09/16 23:59:26]

Done.

+}
+
 void ContentViewCoreImpl::SetFocusInternal(bool focused) {
   if (!GetRenderWidgetHostViewAndroid())
     return;