Prevent background color update during tab switcher exit

This patch prevents a flash in the toolbar when creating new tabs. The
theme color of the toolbar was being set prior to being needed due to
an inconsistency in state in ToolbarPhone. Now, the update logic
blocks theme color updates while exiting the tab switcher and requests
an update once the transition finishes.

Bug: 832594
Change-Id: Idf89eb43a8ce4ed155a815cdfe11147801ef40a6
Reviewed-on: https://chromium-review.googlesource.com/1067715Reviewed-by: Ted Choc <tedchoc@chromium.org>
Reviewed-by: Theresa <twellington@chromium.org>
Commit-Queue: Matthew Jones <mdjones@chromium.org>
Cr-Commit-Position: refs/heads/master@{#560762}

chrome/android/java/src/org/chromium/chrome/browser/toolbar/ToolbarPhone.java

@@ -848,6 +848,7 @@ public class ToolbarPhone extends ToolbarLayout
     }
 
     protected void updateToolbarBackground(int color) {
+        if (mToolbarBackground.getColor() == color) return;
         mToolbarBackground.setColor(color);
         invalidate();
     }
@@ -1965,6 +1966,7 @@ public class ToolbarPhone extends ToolbarLayout
         if (mTabSwitcherState == EXITING_TAB_SWITCHER) {
             mLocationBar.setUrlBarFocusable(true);
             mTabSwitcherState = STATIC_TAB;
+            updateVisualsForToolbarState();
         }
         if (mTabSwitcherState == ENTERING_TAB_SWITCHER) mTabSwitcherState = TAB_SWITCHER;
 
@@ -2569,6 +2571,12 @@ public class ToolbarPhone extends ToolbarLayout
         updateOverlayDrawables();
         updateShadowVisibility();
         updateUrlExpansionAnimation();
+
+        // This exception is to prevent early change of theme color when exiting the tab switcher
+        // since currently visual state does not map correctly to tab switcher state. See
+        // https://crbug.com/832594 for more info.
+        if (mTabSwitcherState != EXITING_TAB_SWITCHER) updateToolbarBackground(mVisualState);
+
         if (!visualStateChanged) {
             if (mVisualState == VisualState.NEW_TAB_NORMAL) {
                 updateNtpTransitionAnimation();
@@ -2581,7 +2589,6 @@ public class ToolbarPhone extends ToolbarLayout
         mUseLightToolbarDrawables = false;
         mUnfocusedLocationBarUsesTransparentBg = false;
         mLocationBarBackgroundAlpha = 255;
-        updateToolbarBackground(mVisualState);
         getProgressBar().setThemeColor(themeColorForProgressBar, isIncognito());
 
         if (inOrEnteringTabSwitcher) {