Remove DWrite locks

src/ports/SkScalerContext_win_dw.cpp

Index: src/ports/SkScalerContext_win_dw.cpp
diff --git a/src/ports/SkScalerContext_win_dw.cpp b/src/ports/SkScalerContext_win_dw.cpp
index c9ff5d86c35e2f8efd0eb5aec882631b0cd2fb13..481ae703e980b521623e88910a4e33d965e476c8 100644
--- a/src/ports/SkScalerContext_win_dw.cpp
+++ b/src/ports/SkScalerContext_win_dw.cpp
@@ -18,7 +18,6 @@
 #include "SkHRESULT.h"
 #include "SkMaskGamma.h"
 #include "SkMatrix22.h"
-#include "SkMutex.h"
 #include "SkOTTable_EBLC.h"
 #include "SkOTTable_EBSC.h"
 #include "SkOTTable_gasp.h"
@@ -27,7 +26,6 @@
 #include "SkRasterClip.h"
 #include "SkScalerContext.h"
 #include "SkScalerContext_win_dw.h"
-#include "SkSharedMutex.h"
 #include "SkTScopedComPtr.h"
 #include "SkTypeface_win_dw.h"
 
@@ -36,20 +34,11 @@
 #  include <dwrite_1.h>
 #endif
 
-/* Note:
- * In versions 8 and 8.1 of Windows, some calls in DWrite are not thread safe.
- * The DWriteFactoryMutex protects the calls that are problematic.
- */
-static SkSharedMutex DWriteFactoryMutex;
-
-typedef SkAutoSharedMutexShared Shared;
-
 static bool isLCD(const SkScalerContext::Rec& rec) {
     return SkMask::kLCD16_Format == rec.fMaskFormat;
 }
 
 static bool is_hinted_without_gasp(DWriteFontTypeface* typeface) {
-    SkAutoExclusive l(DWriteFactoryMutex);
     AutoTDWriteTable<SkOTTableMaximumProfile> maxp(typeface->fDWriteFontFace.get());
     if (!maxp.fExists) {
         return false;
@@ -119,7 +108,6 @@ static void expand_range_if_gridfit_only(DWriteFontTypeface* typeface, int size,
 }
 
 static bool has_bitmap_strike(DWriteFontTypeface* typeface, PPEMRange range) {
-    SkAutoExclusive l(DWriteFactoryMutex);
     {
         AutoTDWriteTable<SkOTTableEmbeddedBitmapLocation> eblc(typeface->fDWriteFontFace.get());
         if (!eblc.fExists) {
@@ -362,7 +350,6 @@ void SkScalerContext_DW::generateAdvance(SkGlyph* glyph) {
     if (DWRITE_MEASURING_MODE_GDI_CLASSIC == fMeasuringMode ||
         DWRITE_MEASURING_MODE_GDI_NATURAL == fMeasuringMode)
     {
-        SkAutoExclusive l(DWriteFactoryMutex);
         HRVM(fTypeface->fDWriteFontFace->GetGdiCompatibleGlyphMetrics(
                  fTextSizeMeasure,
                  1.0f, // pixelsPerDip
@@ -372,16 +359,12 @@ void SkScalerContext_DW::generateAdvance(SkGlyph* glyph) {
                  &gm),
              "Could not get gdi compatible glyph metrics.");
     } else {
-        SkAutoExclusive l(DWriteFactoryMutex);
         HRVM(fTypeface->fDWriteFontFace->GetDesignGlyphMetrics(&glyphId, 1, &gm),
              "Could not get design metrics.");
     }
 
     DWRITE_FONT_METRICS dwfm;
-    {
-        Shared l(DWriteFactoryMutex);
-        fTypeface->fDWriteFontFace->GetMetrics(&dwfm);
-    }
+    fTypeface->fDWriteFontFace->GetMetrics(&dwfm);
     SkScalar advanceX = SkScalarMulDiv(fTextSizeMeasure,
                                        SkIntToScalar(gm.advanceWidth),
                                        SkIntToScalar(dwfm.designUnitsPerEm));
@@ -430,24 +413,18 @@ HRESULT SkScalerContext_DW::getBoundingBox(SkGlyph* glyph,
     run.glyphOffsets = &offset;
 
     SkTScopedComPtr<IDWriteGlyphRunAnalysis> glyphRunAnalysis;
-    {
-        SkAutoExclusive l(DWriteFactoryMutex);
-        HRM(fTypeface->fFactory->CreateGlyphRunAnalysis(
-            &run,
-            1.0f, // pixelsPerDip,
-            &fXform,
-            renderingMode,
-            fMeasuringMode,
-            0.0f, // baselineOriginX,
-            0.0f, // baselineOriginY,
-            &glyphRunAnalysis),
-            "Could not create glyph run analysis.");
-    }
-    {
-        Shared l(DWriteFactoryMutex);
-        HRM(glyphRunAnalysis->GetAlphaTextureBounds(textureType, bbox),
-            "Could not get texture bounds.");
-    }
+    HRM(fTypeface->fFactory->CreateGlyphRunAnalysis(
+        &run,
+        1.0f, // pixelsPerDip,
+        &fXform,
+        renderingMode,
+        fMeasuringMode,
+        0.0f, // baselineOriginX,
+        0.0f, // baselineOriginY,
+        &glyphRunAnalysis),
+        "Could not create glyph run analysis.");
+    HRM(glyphRunAnalysis->GetAlphaTextureBounds(textureType, bbox),
+        "Could not get texture bounds.");
     return S_OK;
 }
 
@@ -735,18 +712,15 @@ const void* SkScalerContext_DW::drawDWMask(const SkGlyph& glyph,
     {
 
         SkTScopedComPtr<IDWriteGlyphRunAnalysis> glyphRunAnalysis;
-        {
-            SkAutoExclusive l(DWriteFactoryMutex);
-            HRNM(fTypeface->fFactory->CreateGlyphRunAnalysis(&run,
-                1.0f, // pixelsPerDip,
-                &fXform,
-                renderingMode,
-                fMeasuringMode,
-                0.0f, // baselineOriginX,
-                0.0f, // baselineOriginY,
-                &glyphRunAnalysis),
-                "Could not create glyph run analysis.");
-        }
+        HRNM(fTypeface->fFactory->CreateGlyphRunAnalysis(&run,
+            1.0f, // pixelsPerDip,
+            &fXform,
+            renderingMode,
+            fMeasuringMode,
+            0.0f, // baselineOriginX,
+            0.0f, // baselineOriginY,
+            &glyphRunAnalysis),
+            "Could not create glyph run analysis.");
         //NOTE: this assumes that the glyph has already been measured
         //with an exact same glyph run analysis.
         RECT bbox;
@@ -754,14 +728,11 @@ const void* SkScalerContext_DW::drawDWMask(const SkGlyph& glyph,
         bbox.top = glyph.fTop;
         bbox.right = glyph.fLeft + glyph.fWidth;
         bbox.bottom = glyph.fTop + glyph.fHeight;
-        {
-            Shared l(DWriteFactoryMutex);
-            HRNM(glyphRunAnalysis->CreateAlphaTexture(textureType,
-                &bbox,
-                fBits.begin(),
-                sizeNeeded),
-                "Could not draw mask.");
-        }
+        HRNM(glyphRunAnalysis->CreateAlphaTexture(textureType,
+            &bbox,
+            fBits.begin(),
+            sizeNeeded),
+            "Could not draw mask.");
     }
     return fBits.begin();
 }
@@ -819,19 +790,16 @@ void SkScalerContext_DW::generateColorGlyphImage(const SkGlyph& glyph) {
         SkTScopedComPtr<IDWriteGeometrySink> geometryToPath;
         HRVM(SkDWriteGeometrySink::Create(&path, &geometryToPath),
              "Could not create geometry to path converter.");
-        {
-            SkAutoExclusive l(DWriteFactoryMutex);
-            HRVM(colorGlyph->glyphRun.fontFace->GetGlyphRunOutline(
-                colorGlyph->glyphRun.fontEmSize,
-                colorGlyph->glyphRun.glyphIndices,
-                colorGlyph->glyphRun.glyphAdvances,
-                colorGlyph->glyphRun.glyphOffsets,
-                colorGlyph->glyphRun.glyphCount,
-                colorGlyph->glyphRun.isSideways,
-                colorGlyph->glyphRun.bidiLevel % 2, //rtl
-                geometryToPath.get()),
-                "Could not create glyph outline.");
-        }
+        HRVM(colorGlyph->glyphRun.fontFace->GetGlyphRunOutline(
+            colorGlyph->glyphRun.fontEmSize,
+            colorGlyph->glyphRun.glyphIndices,
+            colorGlyph->glyphRun.glyphAdvances,
+            colorGlyph->glyphRun.glyphOffsets,
+            colorGlyph->glyphRun.glyphCount,
+            colorGlyph->glyphRun.isSideways,
+            colorGlyph->glyphRun.bidiLevel % 2, //rtl
+            geometryToPath.get()),
+             "Could not create glyph outline.");
         draw.drawPath(path, paint, nullptr, true /* pathIsMutable */);
     }
 }
@@ -897,20 +865,17 @@ void SkScalerContext_DW::generatePath(const SkGlyph& glyph, SkPath* path) {
     HRVM(SkDWriteGeometrySink::Create(path, &geometryToPath),
          "Could not create geometry to path converter.");
     uint16_t glyphId = glyph.getGlyphID();
-    {
-        SkAutoExclusive l(DWriteFactoryMutex);
-        //TODO: convert to<->from DIUs? This would make a difference if hinting.
-        //It may not be needed, it appears that DirectWrite only hints at em size.
-        HRVM(fTypeface->fDWriteFontFace->GetGlyphRunOutline(SkScalarToFloat(fTextSizeRender),
-            &glyphId,
-            nullptr, //advances
-            nullptr, //offsets
-            1, //num glyphs
-            FALSE, //sideways
-            FALSE, //rtl
-            geometryToPath.get()),
-            "Could not create glyph outline.");
-    }
+    //TODO: convert to<->from DIUs? This would make a difference if hinting.
+    //It may not be needed, it appears that DirectWrite only hints at em size.
+    HRVM(fTypeface->fDWriteFontFace->GetGlyphRunOutline(SkScalarToFloat(fTextSizeRender),
+        &glyphId,
+        nullptr, //advances
+        nullptr, //offsets
+        1, //num glyphs
+        FALSE, //sideways
+        FALSE, //rtl
+        geometryToPath.get()),
+        "Could not create glyph outline.");
 
     path->transform(fSkXform);
 }