Fix HDR blownout issue in the Photos app with HDR display on.

- make sure that renderHdrSdrRatio is not larger than current
  mDesiredHdrSdrRatio when updating.
- cleanup setTargetHdrSdrRatio function.

Bug: 276744890
Test: play with Photos
Change-Id: I7fcd5e33633483ff7577d11748874472ad3ca15e

core/java/android/view/ViewRootImpl.java

@@ -5459,7 +5459,7 @@ public final class ViewRootImpl implements ViewParent,
     }
 
     private void updateRenderHdrSdrRatio() {
-        mRenderHdrSdrRatio = mDisplay.getHdrSdrRatio();
+        mRenderHdrSdrRatio = Math.min(mDesiredHdrSdrRatio, mDisplay.getHdrSdrRatio());
         mUpdateHdrSdrRatioInfo = true;
     }
 
@@ -5487,22 +5487,14 @@ public final class ViewRootImpl implements ViewParent,
                 mHdrSdrRatioChangedListener = null;
             } else {
                 mHdrSdrRatioChangedListener = display -> {
-                    setTargetHdrSdrRatio(display.getHdrSdrRatio());
+                    updateRenderHdrSdrRatio();
+                    invalidate();
                 };
                 mDisplay.registerHdrSdrRatioChangedListener(mExecutor, mHdrSdrRatioChangedListener);
             }
         }
     }
 
-    /** happylint */
-    public void setTargetHdrSdrRatio(float ratio) {
-        if (mRenderHdrSdrRatio != ratio) {
-            mRenderHdrSdrRatio = ratio;
-            mUpdateHdrSdrRatioInfo = true;
-            invalidate();
-        }
-    }
-
     @Override
     public void requestChildFocus(View child, View focused) {
         if (DEBUG_INPUT_RESIZE) {