Don’t scale task thumbnails.

- Changing task view thumbnail layout.  In portrait, scale the thumbnail
  to width for portrait screenshots, and apply the same scale to 
  landscape screenshots.  In landscape, scale screenshots up to 1:1, and
  tweak the app transition to clip the sides instead of scaling.
  In both orientations, fill with the background color in the remaining
  space.
- Moving some resources related to the title bar to be calculated 
  programmatically so that we can have different header bar sizes which 
  completely overlap the action bar in the screenshot in each 
  orientation.
- Constraining the task stack width in landscape to portrait

Bug: 27504677
Change-Id: Ic9b6fdde6dd728d9f2d20a8b89c05b3a350edfbf
diff --git a/services/core/java/com/android/server/am/ActivityStack.java b/services/core/java/com/android/server/am/ActivityStack.java
index 26eaa8a..659486f 100644
--- a/services/core/java/com/android/server/am/ActivityStack.java
+++ b/services/core/java/com/android/server/am/ActivityStack.java
@@ -929,7 +929,7 @@
             // use within SystemUI while keeping memory usage low.
             if (ActivityManagerService.TAKE_FULLSCREEN_SCREENSHOTS) {
                 w = h = -1;
-                scale = 0.5f;
+                scale = mService.mFullscreenThumbnailScale;
             }
             return mWindowManager.screenshotApplications(who.appToken, Display.DEFAULT_DISPLAY,
                     w, h, scale);