Prevent crash when setting up a stencil-based clip

Bug #8177690

Clear the layers before we setup the stencil to avoid dereferencing
the recently deleted rects.

Change-Id: I5dce5f965672f276f9490636d85b6018d3ab9422

libs/hwui/OpenGLRenderer.cpp

@@ -1179,6 +1179,10 @@ void OpenGLRenderer::clearLayerRegions() {
 
             delete bounds;
         }
+        // We must clear the list of dirty rects before we
+        // call setupDraw() to prevent stencil setup to do
+        // the same thing again
+        mLayers.clear();
 
         setupDraw(false);
         setupDrawColor(0.0f, 0.0f, 0.0f, 1.0f);
@@ -1195,9 +1199,8 @@ void OpenGLRenderer::clearLayerRegions() {
         for (uint32_t i = 0; i < count; i++) {
             delete mLayers.itemAt(i);
         }
+        mLayers.clear();
     }
-
-    mLayers.clear();
 }
 
 ///////////////////////////////////////////////////////////////////////////////

libs/hwui/font/Font.cpp

@@ -189,7 +189,10 @@ void Font::drawCachedGlyph(CachedGlyphInfo* glyph, float x, float hOffset, float
     vOffset += glyph->mBitmapTop + height;
 
     SkPoint destination[4];
-    measure.getPosTan(x + hOffset + glyph->mBitmapLeft + halfWidth, position, tangent);
+    bool ok = measure.getPosTan(x + hOffset + glyph->mBitmapLeft + halfWidth, position, tangent);
+    if (!ok) {
+        ALOGW("The path for drawTextOnPath is empty or null");
+    }
 
     // Move along the tangent and offset by the normal
     destination[0].set(-tangent->fX * halfWidth - tangent->fY * vOffset,