[Android] Add progress bar linear animation option.

chrome/android/java/src/org/chromium/chrome/browser/widget/ToolbarProgressBar.java

 // Copyright 2015 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.
 
 package org.chromium.chrome.browser.widget;
 
 import android.animation.TimeAnimator;
 import android.animation.TimeAnimator.TimeListener;
 import android.content.Context;
 import android.text.TextUtils;
@@ skipping 88 matching lines @@
         mAnimationInitialized = true;
 
         assert mAnimationLogic == null;
 
         String animation = CommandLine.getInstance().getSwitchValue(
                 ChromeSwitches.PROGRESS_BAR_ANIMATION);
         if (TextUtils.equals(animation, "smooth")) {
             mAnimationLogic = new ProgressAnimationSmooth();
         } else if (TextUtils.equals(animation, "fast-start")) {
             mAnimationLogic = new ProgressAnimationFastStart();
+        } else if (TextUtils.equals(animation, "linear")) {
+            mAnimationLogic = new ProgressAnimationLinear();
+        } else {
+            assert animation == null

[Ted C, 2015/08/07 23:11:00]

Maybe just this instead of the two checks?
http://developer.android.com/reference/android/text/TextUtils.html#isEmpty(ja...

[Kibeom Kim (inactive), 2015/08/07 23:35:34]

Done.

+                    || animation.isEmpty()
+                    || TextUtils.equals(animation, "disabled");
         }
     }
 
     /**
      * Start showing progress bar animation.
      */
     public void start() {
         mIsStarted = true;
         super.setProgress(0.0f);
         if (mAnimationLogic != null) mAnimationLogic.reset();
@@ skipping 59 matching lines @@
 
     @Override
     public void setProgress(float progress) {
         assert mIsStarted;
         assert getProgress() <= progress;
 
         mTargetProgress = progress;
         updateVisibleProgress();
     }
 }