Cleanup unnecessary code in canvas_skia

ui/gfx/canvas_skia.cc

Index: ui/gfx/canvas_skia.cc
diff --git a/ui/gfx/canvas_skia.cc b/ui/gfx/canvas_skia.cc
index 3de9b939bd19cefadda1b84d87999c1902eed241..4ffb974d9c8e22b8805d96550527ee06f33d0d08 100644
--- a/ui/gfx/canvas_skia.cc
+++ b/ui/gfx/canvas_skia.cc
@@ -21,41 +21,6 @@ namespace gfx {
 
 namespace {
 
-#if defined(OS_WIN)
-// If necessary, wraps |text| with RTL/LTR directionality characters based on
-// |flags| and |text| content.
-// Returns true if the text will be rendered right-to-left.
-// TODO(msw): Nix this, now that RenderTextWin supports directionality directly.
-bool AdjustStringDirection(int flags, base::string16* text) {
-  // TODO(msw): FORCE_LTR_DIRECTIONALITY does not work for RTL text now.
-
-  // If the string is empty or LTR was forced, simply return false since the
-  // default RenderText directionality is already LTR.
-  if (text->empty() || (flags & Canvas::FORCE_LTR_DIRECTIONALITY))
-    return false;
-
-  // If RTL is forced, apply it to the string.
-  if (flags & Canvas::FORCE_RTL_DIRECTIONALITY) {
-    base::i18n::WrapStringWithRTLFormatting(text);
-    return true;
-  }
-
-  // If a direction wasn't forced but the UI language is RTL and there were
-  // strong RTL characters, ensure RTL is applied.
-  if (base::i18n::IsRTL() && base::i18n::StringContainsStrongRTLChars(*text)) {
-    base::i18n::WrapStringWithRTLFormatting(text);
-    return true;
-  }
-
-  // In the default case, the string should be rendered as LTR. RenderText's
-  // default directionality is LTR, so the text doesn't need to be wrapped.
-  // Note that individual runs within the string may still be rendered RTL
-  // (which will be the case for RTL text under non-RTL locales, since under RTL
-  // locales it will be handled by the if statement above).
-  return false;
-}
-#endif  // defined(OS_WIN)
-
 // Checks each pixel immediately adjacent to the given pixel in the bitmap. If
 // any of them are not the halo color, returns true. This defines the halo of
 // pixels that will appear around the text. Note that we have to check each
@@ -131,11 +96,14 @@ void UpdateRenderText(const Rect& rect,
   // if not specified.
   if (!(flags & (Canvas::TEXT_ALIGN_CENTER |
                  Canvas::TEXT_ALIGN_RIGHT |
-                 Canvas::TEXT_ALIGN_LEFT))) {
+                 Canvas::TEXT_ALIGN_LEFT |
+                 Canvas::TEXT_ALIGN_TO_HEAD))) {
     flags |= Canvas::DefaultCanvasTextAlignment();
   }
 
-  if (flags & Canvas::TEXT_ALIGN_RIGHT)
+  if (flags & Canvas::TEXT_ALIGN_TO_HEAD)
+    render_text->SetHorizontalAlignment(ALIGN_TO_HEAD);
+  else if (flags & Canvas::TEXT_ALIGN_RIGHT)
     render_text->SetHorizontalAlignment(ALIGN_RIGHT);
   else if (flags & Canvas::TEXT_ALIGN_CENTER)
     render_text->SetHorizontalAlignment(ALIGN_CENTER);
@@ -163,11 +131,6 @@ void Canvas::SizeStringFloat(const base::string16& text,
   DCHECK_GE(*width, 0);
   DCHECK_GE(*height, 0);
 
-  base::string16 adjusted_text = text;
-#if defined(OS_WIN)
-  AdjustStringDirection(flags, &adjusted_text);
-#endif
-
   if ((flags & MULTI_LINE) && *width != 0) {
     WordWrapBehavior wrap_behavior = TRUNCATE_LONG_WORDS;
     if (flags & CHARACTER_BREAK)
@@ -176,7 +139,7 @@ void Canvas::SizeStringFloat(const base::string16& text,
       wrap_behavior = ELIDE_LONG_WORDS;
 
     std::vector<base::string16> strings;
-    ElideRectangleText(adjusted_text, font_list,
+    ElideRectangleText(text, font_list,

[msw, 2015/02/25 17:05:20]

nit: update line wrapping.

[oshima, 2015/03/04 08:01:50]

Done.

                        *width, INT_MAX,
                        wrap_behavior, &strings);
     Rect rect(ClampToInt(*width), INT_MAX);
@@ -198,23 +161,15 @@ void Canvas::SizeStringFloat(const base::string16& text,
     *width = w;
     *height = h;
   } else {
-    // If the string is too long, the call by |RenderTextWin| to |ScriptShape()|
-    // will inexplicably fail with result E_INVALIDARG. Guard against this.
-    const size_t kMaxRenderTextLength = 5000;

[msw, 2015/03/04 17:09:36]

You should update the comment in text_elider.cc referencing this value.
https://code.google.com/p/chromium/codesearch#chromium/src/ui/gfx/text_elider...

-    if (adjusted_text.length() >= kMaxRenderTextLength) {

[msw, 2015/02/25 17:05:20]

Did you test some very long strings here? (up to 10k chars)

[oshima, 2015/03/04 08:01:50]

RenderTextWin no longer exists, so E_INVALIDARG can't happen, can it? 

or do you want me to add test to canvas_unittest? (There is
RenderTexTest.StringSizeLongStrings for RT itself)

[msw, 2015/03/04 17:09:36]

This was unconditionally clamping at 5k chars, even for RTHB, but now this will
pass a string of unbounded length to RenderText. RTHB should truncate at
kMaxTextLength = 10000, and StringSizeLongStrings seems to test this
functionality sufficiently, so I think this will be okay. I just thought it
might be worth testing in practice to ensure we don't hit any crash/hang/jank,
and I wonder if the value of determining the precise size of a string longer
than 5k-10k chars here outwieghs any performance degradation that might occur.

[oshima, 2015/03/04 20:17:42]

In the omibox, which uses TextField that uses RT directly, I tested the long
text
(that I can see elide "..." in omnibox) and I didn't see big performance issue.

-      *width = static_cast<float>(
-          font_list.GetExpectedTextWidth(adjusted_text.length()));
-      *height = static_cast<float>(font_list.GetHeight());
-    } else {
-      scoped_ptr<RenderText> render_text(RenderText::CreateInstance());
-      Rect rect(ClampToInt(*width), ClampToInt(*height));
-      StripAcceleratorChars(flags, &adjusted_text);
-      UpdateRenderText(rect, adjusted_text, font_list, flags, 0,
-                       render_text.get());
-      const SizeF& string_size = render_text->GetStringSizeF();
-      *width = string_size.width();
-      *height = string_size.height();
-    }
+    scoped_ptr<RenderText> render_text(RenderText::CreateInstance());
+    Rect rect(ClampToInt(*width), ClampToInt(*height));
+    base::string16 adjusted_text = text;
+    StripAcceleratorChars(flags, &adjusted_text);
+    UpdateRenderText(rect, adjusted_text, font_list, flags, 0,
+                     render_text.get());
+    const SizeF& string_size = render_text->GetStringSizeF();
+    *width = string_size.width();
+    *height = string_size.height();
   }
 }
 
@@ -235,11 +190,6 @@ void Canvas::DrawStringRectWithShadows(const base::string16& text,
   ClipRect(clip_rect);
 
   Rect rect(text_bounds);
-  base::string16 adjusted_text = text;
-
-#if defined(OS_WIN)
-  AdjustStringDirection(flags, &adjusted_text);
-#endif
 
   scoped_ptr<RenderText> render_text(RenderText::CreateInstance());
   render_text->set_shadows(shadows);
@@ -252,7 +202,7 @@ void Canvas::DrawStringRectWithShadows(const base::string16& text,
       wrap_behavior = ELIDE_LONG_WORDS;
 
     std::vector<base::string16> strings;
-    ElideRectangleText(adjusted_text, font_list,
+    ElideRectangleText(text, font_list,
                        static_cast<float>(text_bounds.width()),
                        text_bounds.height(), wrap_behavior, &strings);
 
@@ -284,6 +234,7 @@ void Canvas::DrawStringRectWithShadows(const base::string16& text,
       rect += Vector2d(0, line_height);
     }
   } else {
+    base::string16 adjusted_text = text;
     Range range = StripAcceleratorChars(flags, &adjusted_text);
     bool elide_text = ((flags & NO_ELLIPSIS) == 0);
 
@@ -373,20 +324,11 @@ void Canvas::DrawFadedString(const base::string16& text,
     DrawStringRectWithFlags(text, font_list, color, display_rect, flags);
     return;
   }
-
-  // Align with forced content directionality, overriding alignment flags.
-  if (flags & FORCE_RTL_DIRECTIONALITY) {
-    flags &= ~(TEXT_ALIGN_CENTER | TEXT_ALIGN_LEFT);
-    flags |= TEXT_ALIGN_RIGHT;
-  } else if (flags & FORCE_LTR_DIRECTIONALITY) {
-    flags &= ~(TEXT_ALIGN_CENTER | TEXT_ALIGN_RIGHT);
-    flags |= TEXT_ALIGN_LEFT;
-  } else if (!(flags & TEXT_ALIGN_LEFT) && !(flags & TEXT_ALIGN_RIGHT)) {
-    // Also align with content directionality instead of fading both ends.
+  if (!(flags &
+        (TEXT_ALIGN_LEFT | TEXT_ALIGN_RIGHT | TEXT_ALIGN_TO_HEAD))) {
+    // align with content directionality instead of fading both ends.

[msw, 2015/02/25 17:05:20]

nit: Align

[oshima, 2015/03/04 08:01:50]

Done.

     flags &= ~TEXT_ALIGN_CENTER;

[msw, 2015/02/25 17:05:20]

nit: refactor the code to unconditionally prevent center fading:
  // Align with content directionality instead of fading both ends.
  flags &= ~TEXT_ALIGN_CENTER;
  if (!(flags & (TEXT_ALIGN_LEFT | TEXT_ALIGN_RIGHT)))
    flags |= TEXT_ALIGN_TO_HEAD;

[oshima, 2015/03/04 08:01:50]

Done.

-    const bool is_rtl = base::i18n::GetFirstStrongCharacterDirection(text) ==
-                        base::i18n::RIGHT_TO_LEFT;
-    flags |= is_rtl ? TEXT_ALIGN_RIGHT : TEXT_ALIGN_LEFT;
+    flags |= TEXT_ALIGN_TO_HEAD;
   }
   flags |= NO_ELLIPSIS;