Improve debugging setup for window manager package.

This moves debug flags to a dedicated class and also provides a
mechanism to either have fine grained tags or one common tag for easier
grepping the logcat. This mimicks the approach in activity manager
package.

Change-Id: Ie8c08b9a3d8b182335ee5547ee05d21b5933db6b
diff --git a/services/core/java/com/android/server/wm/AccessibilityController.java b/services/core/java/com/android/server/wm/AccessibilityController.java
index a4b4276..e6b649e7 100644
--- a/services/core/java/com/android/server/wm/AccessibilityController.java
+++ b/services/core/java/com/android/server/wm/AccessibilityController.java
@@ -16,6 +16,9 @@
 
 package com.android.server.wm;
 
+import static com.android.server.wm.WindowManagerDebugConfig.TAG_WITH_CLASS_NAME;
+import static com.android.server.wm.WindowManagerDebugConfig.TAG_WM;
+
 import android.animation.ObjectAnimator;
 import android.animation.ValueAnimator;
 import android.app.Service;
@@ -219,7 +222,7 @@
      */
     private static final class DisplayMagnifier {
 
-        private static final String LOG_TAG = "DisplayMagnifier";
+        private static final String LOG_TAG = TAG_WITH_CLASS_NAME ? "DisplayMagnifier" : TAG_WM;
 
         private static final boolean DEBUG_WINDOW_TRANSITIONS = false;
         private static final boolean DEBUG_ROTATION = false;
@@ -925,7 +928,8 @@
      * user can see on the screen.
      */
     private static final class WindowsForAccessibilityObserver {
-        private static final String LOG_TAG = "WindowsForAccessibilityObserver";
+        private static final String LOG_TAG = TAG_WITH_CLASS_NAME ?
+                "WindowsForAccessibilityObserver" : TAG_WM;
 
         private static final boolean DEBUG = false;