[Android] Fix crashes on Chrome internal pages.

chrome/android/java/src/org/chromium/chrome/browser/compositor/CompositorViewHolder.java

Index: chrome/android/java/src/org/chromium/chrome/browser/compositor/CompositorViewHolder.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/compositor/CompositorViewHolder.java b/chrome/android/java/src/org/chromium/chrome/browser/compositor/CompositorViewHolder.java
index 2c744fc86b10d88575ee17756b361e61a1133d72..06df8640b22bef471a31d71af1e53aed57035b9f 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/compositor/CompositorViewHolder.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/compositor/CompositorViewHolder.java
@@ -223,7 +223,6 @@ public class CompositorViewHolder extends FrameLayout
             }
         });
 
-        if (!DeviceFormFactor.isTablet(getContext())) mProgressBarDrawingInfo = new DrawingInfo();
         mCompositorView = new CompositorView(getContext(), this);
         addView(mCompositorView,
                 new FrameLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT));
@@ -541,9 +540,14 @@ public class CompositorViewHolder extends FrameLayout
         TraceEvent.begin("CompositorViewHolder:layout");
         if (mLayoutManager != null) {
             mLayoutManager.onUpdate();
-            if (mProgressBarDrawingInfo != null) {
+
+            if (!DeviceFormFactor.isTablet(getContext()) && mControlContainer != null) {
+                if (mProgressBarDrawingInfo == null) mProgressBarDrawingInfo = new DrawingInfo();
                 mControlContainer.getProgressBarDrawingInfo(mProgressBarDrawingInfo);
+            } else {
+                mProgressBarDrawingInfo = null;

[Ted C, 2015/07/30 15:02:13]

why do you need to set it to null here?

does the drawing code handle it if we go from non-null to null?  Does null clear
out the progress bar or would it leave it drawing the old state?

[Kibeom Kim (inactive), 2015/07/30 17:00:28]

Done.

(Changed to assert since we expect mControlContainer to be initialized only
once, but I can also change to handle clearing)

             }
+
             mCompositorView.finalizeLayers(mLayoutManager, mSkipNextToolbarTextureUpdate,
                     mProgressBarDrawingInfo);