Consolidate Windows bitmap and DC code

skia/ext/skia_utils_win.cc

Index: skia/ext/skia_utils_win.cc
diff --git a/skia/ext/skia_utils_win.cc b/skia/ext/skia_utils_win.cc
index 37bd21e3c898ac1cd0432d89f0c6d999983773c9..e234da6756613d3e8f92f9a4a7661cf8de7a1aa4 100644
--- a/skia/ext/skia_utils_win.cc
+++ b/skia/ext/skia_utils_win.cc
@@ -7,9 +7,9 @@
 #include <stddef.h>
 #include <windows.h>
 
+#include "base/debug/gdi_debug_util_win.h"
 #include "third_party/skia/include/core/SkRect.h"
 #include "third_party/skia/include/core/SkTypes.h"
-#include "third_party/skia/include/effects/SkGradientShader.h"
 
 namespace {
 
@@ -23,6 +23,24 @@ static_assert(sizeof(RECT().right) == sizeof(SkIRect().fRight), "o7");
 static_assert(sizeof(RECT().bottom) == sizeof(SkIRect().fBottom), "o8");
 static_assert(sizeof(RECT) == sizeof(SkIRect), "o9");
 
+void CreateBitmapHeaderWithColorDepth(LONG width,
+                                      LONG height,
+                                      WORD color_depth,
+                                      BITMAPINFOHEADER* hdr) {
+  // These values are shared with gfx::PlatformDevice.
+  hdr->biSize = sizeof(BITMAPINFOHEADER);
+  hdr->biWidth = width;
+  hdr->biHeight = -height;  // Minus means top-down bitmap.
+  hdr->biPlanes = 1;
+  hdr->biBitCount = color_depth;
+  hdr->biCompression = BI_RGB;  // No compression.
+  hdr->biSizeImage = 0;
+  hdr->biXPelsPerMeter = 1;
+  hdr->biYPelsPerMeter = 1;
+  hdr->biClrUsed = 0;
+  hdr->biClrImportant = 0;
+}
+
 }  // namespace
 
 namespace skia {
@@ -73,7 +91,7 @@ void InitializeDC(HDC context) {
   SkASSERT(res != 0);
   // As per SetStretchBltMode() documentation, SetBrushOrgEx() must be called
   // right after.
-  res = SetBrushOrgEx(context, 0, 0, NULL);
+  res = SetBrushOrgEx(context, 0, 0, nullptr);
   SkASSERT(res != 0);
 
   // Sets up default orientation.
@@ -148,5 +166,32 @@ void CopyHDC(HDC source, HDC destination, int x, int y, bool is_opaque,
   LoadTransformToDC(source, transform);
 }
 
+void CreateBitmapHeader(int width, int height, BITMAPINFOHEADER* hdr) {
+  CreateBitmapHeaderWithColorDepth(width, height, 32, hdr);
+}
+
+HBITMAP CreateHBitmap(int width, int height, HANDLE shared_section, void** data) {
+  // CreateDIBSection fails to allocate anything if we try to create an empty
+  // bitmap, so just create a minimal bitmap.
+  if ((width == 0) || (height == 0)) {
+    width = 1;
+    height = 1;
+  }
+
+  BITMAPINFOHEADER hdr = {0};
+  CreateBitmapHeaderWithColorDepth(width, height, 32, &hdr);
+
+  HBITMAP hbitmap = CreateDIBSection(nullptr,
+                                     reinterpret_cast<BITMAPINFO*>(&hdr),
+                                     0, data, shared_section, 0);
+
+  // If CreateDIBSection() failed, try to get some useful information out
+  // before we crash for post-mortem analysis.
+  if (!hbitmap)
+    base::debug::GDIBitmapAllocFailure(&hdr, shared_section);
+
+  return hbitmap;
+}
+
 }  // namespace skia