work around a problem where fp registers get corrupted (DO NOT MERGE)

Bug: 5331198
Change-Id: I1f9b4a79d34d63f8adb0555909998664ea2ea9ca

Author: pixelflinger

libs/hwui/LayerRenderer.cpp

@@ -31,16 +31,20 @@ namespace uirenderer {
 // Rendering
 ///////////////////////////////////////////////////////////////////////////////
 
+Rect* gHackDontCorruptRegisters;
+
 void LayerRenderer::prepareDirty(float left, float top, float right, float bottom, bool opaque) {
     LAYER_RENDERER_LOGD("Rendering into layer, fbo = %d", mLayer->getFbo());
 
+    Rect dirty(left, top, right, bottom);
+    gHackDontCorruptRegisters = &dirty;
+
     glBindFramebuffer(GL_FRAMEBUFFER, mLayer->getFbo());
 
     const float width = mLayer->layer.getWidth();
     const float height = mLayer->layer.getHeight();
 
 #if RENDER_LAYERS_AS_REGIONS
-    Rect dirty(left, top, right, bottom);
     if (dirty.isEmpty() || (dirty.left <= 0 && dirty.top <= 0 &&
             dirty.right >= width && dirty.bottom >= height)) {
         mLayer->region.clear();