[WIP] Import all canvas layers, rather than just topmost

android_webview/public/browser/draw_sw.h

Index: android_webview/public/browser/draw_sw.h
diff --git a/android_webview/public/browser/draw_sw.h b/android_webview/public/browser/draw_sw.h
index 463f59cb1f57db12817df662741cae32576cbebf..fce5d30b5a2bf02420b40d64d5039ffbb80c139d 100644
--- a/android_webview/public/browser/draw_sw.h
+++ b/android_webview/public/browser/draw_sw.h
@@ -14,7 +14,7 @@
 
 class SkPicture;
 
-static const int kAwPixelInfoVersion = 2;
+static const int kAwPixelInfoVersion = 3;
 
 // Values of the AwPixelInfo::config field.
 enum AwPixelConfig {
@@ -23,18 +23,24 @@ enum AwPixelConfig {
   AwConfig_ARGB_8888 = 6,
 };
 
+struct AwBitmapInfo {
+  int x, y;         // Position of this bitmap in the canvas.
+  int config;       // |pixel| format: a value from AwPixelConfig.
+  int width;        // In pixels.
+  int height;       // In pixels.
+  int row_bytes;    // Number of bytes from start of one line to next.
+  void* pixels;     // The pixels, all (height * row_bytes) of them.
+};
+
 // Holds the information required to implement the SW draw to system canvas.
 struct AwPixelInfo {
   int version;          // The kAwPixelInfoVersion this struct was built with.
-  int config;           // |pixel| format: a value from AwPixelConfig.
-  int width;            // In pixels.
-  int height;           // In pixels.
-  int row_bytes;        // Number of bytes from start of one line to next.
-  void* pixels;         // The pixels, all (height * row_bytes) of them.
   // The Matrix and Clip are relative to |pixels|, not the source canvas.
   float matrix[9];      // The matrix currently in effect on the canvas.
   int clip_rect_count;  // Number of rects in |clip_rects|.
   int* clip_rects;      // Clip area: 4 ints per rect in {x,y,w,h} format.
+  int layer_count;      // Numer of AwBitmapInfo instance in |layers|.
+  AwBitmapInfo* layers; // The bitmap layers, ordered from root upwards.
   // NOTE: If you add more members, bump kAwPixelInfoVersion.
 };