NavBar: Don't resize in portrait docks when HDMI connected.

The computation moving the navbar up is too drastic when a device locked
in a portrait dock is connected to a landscape external display (e.g. a TV).
Instead, only do this if the aspect ratios of the device and external display
are the same.

Bug: 6513219
Change-Id: I7cfb1096b7d1a774032d22c4b0d7eb3177766c58

Author: dsandler

policy/src/com/android/internal/policy/impl/PhoneWindowManager.java

@@ -2278,7 +2278,12 @@ public void beginLayoutLw(int displayWidth, int displayHeight, int displayRotati
                 // It's a system nav bar or a portrait screen; nav bar goes on bottom.
                 int top = displayHeight - mNavigationBarHeightForRotation[displayRotation];
                 if (mHdmiPlugged) {
-                    if (top > mExternalDisplayHeight) {
+                    // Move the nav bar up if the external display is the same aspect ratio
+                    // but shorter.  This avoids clipping on the external display.
+                    boolean sameAspect = mExternalDisplayHeight > 0 && displayHeight > 0
+                        && ((float) mExternalDisplayWidth / mExternalDisplayHeight > 1)
+                        == ((float) displayWidth / displayHeight > 1);
+                    if (sameAspect && top > mExternalDisplayHeight) {
                         top = mExternalDisplayHeight;
                     }
                 }