Add forceDrawNextFrame function for HardwareRenderer

The forceDraw flag in HardwareRenderer will ensure a frame is drawn when
requested even if it would end up drawing multiple frames in a single
vsync.

This is to help blast sync when we want to synchronize the
buffer. We want to make sure we are guaranteed a callback since we don't
want to wait for retries, especially in the case when trying to synchronize
multiple buffers.

There was already a global flag to handle this, but would use the flag
for all draws. This new function is set per draw so once a frame is
drawn it's unset. The global flag was only used for tests so updated the
test to set the flag before every draw and deleted the global property.

Test: Underlying code was in place. This is just piping a new setter. No
usages yet.
Test: TestSceneRunner
Bug: 200284684

Change-Id: Ie1c9950cabb7331cfed1721564a51a1a15cd1624

libs/hwui/renderthread/DrawFrameTask.cpp

@@ -148,6 +148,8 @@ void DrawFrameTask::run() {
     bool canDrawThisFrame;
     {
         TreeInfo info(TreeInfo::MODE_FULL, *mContext);
+        info.forceDrawFrame = mForceDrawFrame;
+        mForceDrawFrame = false;
         canUnblockUiThread = syncFrameState(info);
         canDrawThisFrame = info.out.canDrawThisFrame;