Supports gfx::FontList in gfx::Canvas and ui::ElideText family.

ui/gfx/canvas_ios.mm

Index: ui/gfx/canvas_ios.mm
diff --git a/ui/gfx/canvas_ios.mm b/ui/gfx/canvas_ios.mm
new file mode 100644
index 0000000000000000000000000000000000000000..da431e82a72430687e67a4cb1df9e6695e4ad7c7
--- /dev/null
+++ b/ui/gfx/canvas_ios.mm
@@ -0,0 +1,44 @@
+// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "ui/gfx/canvas.h"
+
+#import <UIKit/UIKit.h>
+
+#include <algorithm>
+#include <cmath>
+
+#include "base/logging.h"
+#include "base/strings/sys_string_conversions.h"
+#include "ui/gfx/font_list.h"
+
+namespace gfx {
+
+// static
+void Canvas::SizeStringInt(const base::string16& text,
+                           const gfx::FontList& font_list,
+                           int* width,
+                           int* height,
+                           int line_height,
+                           int flags) {
+  DLOG_IF(WARNING, line_height != 0) << "Line height not implemented.";
+  DLOG_IF(WARNING, flags & Canvas::MULTI_LINE) << "Multi-line not implemented.";
+
+  NSString* ns_text = base::SysUTF16ToNSString(text);
+  CGSize size = [ns_text
+      sizeWithFont:font_list.GetPrimaryFont().GetNativeFont()];

[Alexei Svitkine (slow), 2013/08/19 14:17:28]

Nit: Extract NativeFont into a local var so that this stays on one line.

[msw, 2013/08/19 19:05:43]

Could this implementation be merged with canvas_mac.mm's? Or must we use
sizeWithFont on iOS because sizeWithAttributes is only supported on iOS7?
http://stackoverflow.com/questions/18154345/sizewithattributes-causes-crash-o...

[stuartmorgan, 2013/08/19 22:08:11]

This is the public documentation for the iOS equivalent of the additions:
https://developer.apple.com/library/ios/documentation/uikit/reference/NSStrin...
and sizeWithAttributes isn't there, so we can't use it.

Whether or not it exists in betas of an as-yet-unreleased SDK for iOS 7 would be
subject to NDA. (But it's irrelevant, because we need to continue to run on
older OS versions.)

[Yuki, 2013/08/20 15:05:47]

Done.

+  *width = std::ceil(size.width);
+  *height = std::max(static_cast<int>(std::ceil(size.height)),
+                     font_list.GetHeight());
+}
+
+// static
+int Canvas::GetStringWidth(const base::string16& text,
+                           const gfx::FontList& font_list) {
+  int width = 0, height = 0;
+  SizeStringInt(text, font_list, &width, &height, 0, NO_ELLIPSIS);
+  return width;
+}
+
+}  // namespace gfx