Fix incognito progressbar color on tablet

Dynamic inflation of the progress bar caused it's color to be
incorrect on incognito tabs. This change modifies the ToolbarTablet
to set the appropriate color whenever the tab's model changes.

BUG=698715

Review-Url: https://codereview.chromium.org/2742573006
Cr-Commit-Position: refs/heads/master@{#456201}

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

@@ -333,8 +333,11 @@ public class ToolbarTablet extends ToolbarLayout implements OnClickListener {
         super.onTabOrModelChanged();
         boolean incognito = isIncognito();
         if (mUseLightColorAssets == null || mUseLightColorAssets != incognito) {
-            setBackgroundResource(incognito
-                    ? R.color.incognito_primary_color : R.color.default_primary_color);
+            int colorResource =
+                    incognito ? R.color.incognito_primary_color : R.color.default_primary_color;
+            setBackgroundResource(colorResource);
+            getProgressBar().setThemeColor(
+                    ApiCompatibilityUtils.getColor(getResources(), colorResource), isIncognito());
 
             mMenuButton.setTint(incognito ? mLightModeTint : mDarkModeTint);
             mHomeButton.setTint(incognito ? mLightModeTint : mDarkModeTint);