Fix bug, change crashes to warnings

Improve behavior when we get a call to draw 0 points.
Replace one ALWAYS_FATAL statements with noop.

Change-Id: I864b7a9633dfa3dc6eefa403beca4cc7ae14074f
diff --git a/libs/hwui/DisplayListRenderer.h b/libs/hwui/DisplayListRenderer.h
index 71c1fc3..d313c18 100644
--- a/libs/hwui/DisplayListRenderer.h
+++ b/libs/hwui/DisplayListRenderer.h
@@ -216,7 +216,7 @@
     virtual void drawVertices(SkCanvas::VertexMode vertexMode, int vertexCount,
             const float* verts, const float* tex, const int* colors,
             const uint16_t* indices, int indexCount, const SkPaint& paint) override
-        { LOG_ALWAYS_FATAL("DisplayListRenderer does not support drawVertices()"); }
+        { /* DisplayListRenderer does not support drawVertices(); ignore */ }
 
     // Bitmap-based
     virtual void drawBitmap(const SkBitmap& bitmap, float left, float top, const SkPaint* paint) override;
diff --git a/libs/hwui/SkiaCanvasProxy.cpp b/libs/hwui/SkiaCanvasProxy.cpp
index 3c65705..ec1bb90 100644
--- a/libs/hwui/SkiaCanvasProxy.cpp
+++ b/libs/hwui/SkiaCanvasProxy.cpp
@@ -22,9 +22,10 @@
 namespace android {
 namespace uirenderer {
 
-SkiaCanvasProxy::SkiaCanvasProxy(Canvas* canvas)
+SkiaCanvasProxy::SkiaCanvasProxy(Canvas* canvas, bool filterHwuiCalls)
         : INHERITED(canvas->width(), canvas->height())
-        , mCanvas(canvas) {}
+        , mCanvas(canvas)
+        , mFilterHwuiCalls(filterHwuiCalls) {}
 
 void SkiaCanvasProxy::onDrawPaint(const SkPaint& paint) {
     mCanvas->drawPaint(paint);
@@ -32,6 +33,10 @@
 
 void SkiaCanvasProxy::onDrawPoints(PointMode pointMode, size_t count, const SkPoint pts[],
         const SkPaint& paint) {
+    if (!pts || count == 0) {
+        return;
+    }
+
     // convert the SkPoints into floats
     SK_COMPILE_ASSERT(sizeof(SkPoint) == sizeof(float)*2, SkPoint_is_no_longer_2_floats);
     const size_t floatCount = count << 1;
@@ -118,6 +123,9 @@
 void SkiaCanvasProxy::onDrawVertices(VertexMode mode, int vertexCount, const SkPoint vertices[],
         const SkPoint texs[], const SkColor colors[], SkXfermode*, const uint16_t indices[],
         int indexCount, const SkPaint& paint) {
+    if (mFilterHwuiCalls) {
+        return;
+    }
     // convert the SkPoints into floats
     SK_COMPILE_ASSERT(sizeof(SkPoint) == sizeof(float)*2, SkPoint_is_no_longer_2_floats);
     const int floatCount = vertexCount << 1;
@@ -312,6 +320,9 @@
 
 void SkiaCanvasProxy::onDrawPatch(const SkPoint cubics[12], const SkColor colors[4],
         const SkPoint texCoords[4], SkXfermode* xmode, const SkPaint& paint) {
+    if (mFilterHwuiCalls) {
+        return;
+    }
     SkPatchUtils::VertexData data;
 
     SkMatrix matrix;
diff --git a/libs/hwui/SkiaCanvasProxy.h b/libs/hwui/SkiaCanvasProxy.h
index 4322fcf..0de9650 100644
--- a/libs/hwui/SkiaCanvasProxy.h
+++ b/libs/hwui/SkiaCanvasProxy.h
@@ -27,16 +27,19 @@
 
 /**
  * This class serves as a proxy between Skia's SkCanvas and Android Framework's
- * Canvas.  The class does not maintain any state and will pass through any request
- * directly to the Canvas provided in the constructor.
+ * Canvas.  The class does not maintain any draw-related state and will pass
+ * through most requests directly to the Canvas provided in the constructor.
  *
  * Upon construction it is expected that the provided Canvas has already been
  * prepared for recording and will continue to be in the recording state while
  * this proxy class is being used.
+ *
+ * If filterHwuiCalls is true, the proxy silently ignores away draw calls that
+ * aren't supported by HWUI.
  */
 class ANDROID_API SkiaCanvasProxy : public SkCanvas {
 public:
-    SkiaCanvasProxy(Canvas* canvas);
+    SkiaCanvasProxy(Canvas* canvas, bool filterHwuiCalls = false);
     virtual ~SkiaCanvasProxy() {}
 
 protected:
@@ -94,6 +97,7 @@
 
 private:
     Canvas* mCanvas;
+    bool mFilterHwuiCalls;
 
     typedef SkCanvas INHERITED;
 };