Fixing crash when taking screenshot over secure window.

Change-Id: If3d4e458030e37aae3310b23dcad2ff5fe29fa73

Author: Winson Chung

packages/SystemUI/src/com/android/systemui/screenshot/GlobalScreenshot.java

@@ -358,7 +358,15 @@ void takeScreenshot(Runnable finisher, boolean statusBarVisible, boolean navBarV
             dims[0] = Math.abs(dims[0]);
             dims[1] = Math.abs(dims[1]);
         }
+
+        // Take the screenshot
         mScreenBitmap = Surface.screenshot((int) dims[0], (int) dims[1]);
+        if (mScreenBitmap == null) {
+            notifyScreenshotError(mContext, mNotificationManager);
+            finisher.run();
+            return;
+        }
+
         if (requiresRotation) {
             // Rotate the screenshot to the current orientation
             Bitmap ss = Bitmap.createBitmap(mDisplayMetrics.widthPixels,
@@ -372,13 +380,6 @@ void takeScreenshot(Runnable finisher, boolean statusBarVisible, boolean navBarV
             mScreenBitmap = ss;
         }
 
-        // If we couldn't take the screenshot, notify the user
-        if (mScreenBitmap == null) {
-            notifyScreenshotError(mContext, mNotificationManager);
-            finisher.run();
-            return;
-        }
-
         // Optimizations
         mScreenBitmap.setHasAlpha(false);
         mScreenBitmap.prepareToDraw();