Add observers for DIP scale change.

content/public/android/java/src/org/chromium/content/browser/RenderCoordinates.java

Index: content/public/android/java/src/org/chromium/content/browser/RenderCoordinates.java
diff --git a/content/public/android/java/src/org/chromium/content/browser/RenderCoordinates.java b/content/public/android/java/src/org/chromium/content/browser/RenderCoordinates.java
index 2df4f974938fc00b0ed8930b8fab2d0c6fdca053..367e7eeb844d001e58eec9729b48594b5d60f477 100644
--- a/content/public/android/java/src/org/chromium/content/browser/RenderCoordinates.java
+++ b/content/public/android/java/src/org/chromium/content/browser/RenderCoordinates.java
@@ -7,9 +7,7 @@ package org.chromium.content.browser;
 import android.content.Context;
 import android.util.TypedValue;
 
-import org.chromium.base.CommandLine;
 import org.chromium.base.VisibleForTesting;
-import org.chromium.content.common.ContentSwitches;
 
 /**
  * Cached copy of all positions and scales (CSS-to-DIP-to-physical pixels)
@@ -62,13 +60,11 @@ public class RenderCoordinates {
         mContentHeightCss = contentHeightCss;
     }
 
-    void setDeviceScaleFactor(Context context) {
-        String forceScaleFactor =
-                CommandLine.getInstance().getSwitchValue(ContentSwitches.FORCE_DEVICE_SCALE_FACTOR);
-        mDeviceScaleFactor = forceScaleFactor != null
-                ? Float.valueOf(forceScaleFactor)
-                : context.getResources().getDisplayMetrics().density;
+    void setDeviceScaleFactor(float dipScale) {

[boliu, 2016/09/14 04:35:32]

why separate these if you just end up calling these two things together?

[Tima Vaisburd, 2016/09/15 00:05:04]

Combined.

+        mDeviceScaleFactor = dipScale;
+    }
 
+    void setWheelScrollFactor(Context context) {
         // The wheel scroll factor depends on the theme in the context.
         // This code assumes that the theme won't change between this call and
         // getWheelScrollScale().