Allows arbitrary scale factor in ImageSkia.

ui/gfx/image/image_skia.cc

Index: ui/gfx/image/image_skia.cc
diff --git a/ui/gfx/image/image_skia.cc b/ui/gfx/image/image_skia.cc
index a283117db2415488f3259cb3986fa956c0031a47..0283969faed0b556d86b83118da813d723bae58e 100644
--- a/ui/gfx/image/image_skia.cc
+++ b/ui/gfx/image/image_skia.cc
@@ -8,14 +8,17 @@
 #include <cmath>
 #include <limits>
 
+#include "base/command_line.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/threading/non_thread_safe.h"
+#include "ui/gfx/geometry/size_conversions.h"
 #include "ui/gfx/image/image_skia_operations.h"
 #include "ui/gfx/image/image_skia_source.h"
 #include "ui/gfx/rect.h"
 #include "ui/gfx/size.h"
 #include "ui/gfx/skia_util.h"
+#include "ui/gfx/switches.h"
 
 namespace gfx {
 namespace {
@@ -27,6 +30,16 @@ gfx::ImageSkiaRep& NullImageRep() {
 }
 
 std::vector<float>* g_supported_scales = NULL;
+
+bool IsImageSkiaScaling() {

[oshima, 2014/05/06 18:52:27]

how about IsDSFScalingInImageSkiaEnabled ?

[Jun Mukai, 2014/05/06 19:56:49]

Done.

+#if defined(OS_WIN)
+  return true;
+#else
+  return base::CommandLine::ForCurrentProcess()->HasSwitch(
+      switches::kAllowArbitraryScaleFactorInImageSkia);
+#endif
+}
+
 }  // namespace
 
 namespace internal {
@@ -139,7 +152,28 @@ class ImageSkiaStorage : public base::RefCountedThreadSafe<ImageSkiaStorage>,
       DCHECK(CalledOnValidThread()) <<
           "An ImageSkia with the source must be accessed by the same thread.";
 
-      ImageSkiaRep image = source_->GetImageForScale(scale);
+      ImageSkiaRep image;
+      if (IsImageSkiaScaling() && scale != 1.0f && scale != 2.0f) {

[oshima, 2014/05/06 18:52:27]

can you use g_supported_scales?

[Jun Mukai, 2014/05/06 19:56:49]

Well, that's still unclear to me. What is g_supported_scales?  Isn't it the DSFs
supported by ImageSkia?  Then, it sounds like it should contain 1.25 or
something.

Here means the scale factor supported by the resource bundle (more strictly
ImageSkiaSource but that doesn't matter right now), right? How does it come?

[Jun Mukai, 2014/05/06 20:42:42]

Chatted offline and I was wrong. g_supported_scales is the scale factors of
resources.  Changed the code to look up g_supported_scales.
Also revised the test.

+        std::vector<ImageSkiaRep>::iterator iter =
+            non_const->FindRepresentation(
+                (scale < 1.0f) ? 1.0f : 2.0f, fetch_new_image);
+
+        DCHECK(iter != non_const->image_reps().end());
+        SkBitmap scaled_image;
+        gfx::Size unscaled_size(iter->pixel_width(), iter->pixel_height());
+        gfx::Size scaled_size = ToCeiledSize(
+            gfx::ScaleSize(unscaled_size, scale / iter->scale()));
+
+        image = ImageSkiaRep(skia::ImageOperations::Resize(
+            iter->sk_bitmap(),
+            skia::ImageOperations::RESIZE_LANCZOS3,
+            scaled_size.width(),
+            scaled_size.height()), scale);
+        DCHECK_EQ(image.pixel_width(), scaled_size.width());
+        DCHECK_EQ(image.pixel_height(), scaled_size.height());
+      } else {
+        image = source_->GetImageForScale(scale);
+      }
 
       // If the source returned the new image, store it.
       if (!image.is_null() &&