Make WebView respond to device scale change

content/browser/android/content_view_core_impl.cc

 // Copyright 2012 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 "content/browser/android/content_view_core_impl.h"
 
 #include <stddef.h>
 
 #include "base/android/jni_android.h"
 #include "base/android/jni_array.h"
@@ skipping 411 matching lines @@
     const gfx::SizeF& viewport_size,
     const gfx::Vector2dF& controls_offset,
     const gfx::Vector2dF& content_offset,
     bool is_mobile_optimized_hint,
     const gfx::SelectionBound& selection_start) {
   JNIEnv* env = AttachCurrentThread();
   ScopedJavaLocalRef<jobject> obj = java_ref_.get(env);
   if (obj.is_null() || !view_.GetWindowAndroid())
     return;
 
-  view_.GetWindowAndroid()->set_content_offset(
-      gfx::ScaleVector2d(content_offset, dpi_scale_));
+  view_.GetWindowAndroid()->set_content_offset(content_offset);

[boliu, 2016/08/16 15:03:03]

this change and it's fallout can be in a separate CL that's landed first

[Tima Vaisburd, 2016/08/16 20:55:28]

Created https://codereview.chromium.org/2249243002/

 
   page_scale_ = page_scale_factor;
 
   // The CursorAnchorInfo API in Android only supports zero width selection
   // bounds.
   const jboolean has_insertion_marker =
       selection_start.type() == gfx::SelectionBound::CENTER;
   const jboolean is_insertion_marker_visible = selection_start.visible();
   const jfloat insertion_marker_horizontal =
       has_insertion_marker ? selection_start.edge_top().x() : 0.0f;
@@ skipping 458 matching lines @@
 WebContents* ContentViewCoreImpl::GetWebContents() const {
   return web_contents_;
 }
 
 void ContentViewCoreImpl::SetFocus(JNIEnv* env,
                                    const JavaParamRef<jobject>& obj,
                                    jboolean focused) {
   SetFocusInternal(focused);
 }
 
+void ContentViewCoreImpl::SetDeviceScaleFactor(JNIEnv* env,
+                                               const JavaParamRef<jobject>& obj,
+                                               jfloat device_scale) {
+  DVLOG(1) << __FUNCTION__ << " " << device_scale;
+  dpi_scale_ = device_scale;

[boliu, 2016/08/16 15:03:03]

what about all the places where dpi_scale() is called? that's a lot of places

+}
+
 void ContentViewCoreImpl::SetFocusInternal(bool focused) {
   if (!GetRenderWidgetHostViewAndroid())
     return;
 
   if (focused)
     GetRenderWidgetHostViewAndroid()->Focus();
   else
     GetRenderWidgetHostViewAndroid()->Blur();
 }
 
@@ skipping 716 matching lines @@
     return ScopedJavaLocalRef<jobject>();
 
   return view->GetJavaObject();
 }
 
 bool RegisterContentViewCore(JNIEnv* env) {
   return RegisterNativesImpl(env);
 }
 
 }  // namespace content