Bug 1404370 - TextDrawTarget: add fallbacks for remaining cases, remove some hacks. r=jrmuizel

This adds fallbacks for:
* synthetic bold
* synthetic italics
* text-writing-modes

This also removes an old hack to make synthetic italics less broken.

This also prevents special opacity handling for color fonts so that webrender
gets that information.

MozReview-Commit-ID: DKiTUBR6hzy

--HG--
extra : rebase_source : 22b445d40ee46bb09d4325828a8e959d3da7a9c7

gfx/thebes/gfxFont.cpp

@@ -2084,6 +2084,12 @@ gfxFont::Draw(const gfxTextRun *aTextRun, uint32_t aStart, uint32_t aEnd,
 
     gfxPoint origPt = *aPt;
     if (aRunParams.isVerticalRun && !fontParams.isVerticalFont) {
+
+        if (textDrawer) {
+            textDrawer->FoundUnsupportedFeature();
+            return;
+        }
+
         sideways = true;
         matrixRestore.SetContext(aRunParams.context);
         gfxPoint p(aPt->x * aRunParams.devPerApp,
@@ -2139,6 +2145,11 @@ gfxFont::Draw(const gfxTextRun *aTextRun, uint32_t aStart, uint32_t aEnd,
             // use as many strikes as needed for the the increased advance
             fontParams.extraStrikes =
                 std::max(1, NS_lroundf(GetSyntheticBoldOffset() / xscale));
+
+            if (textDrawer) {
+                textDrawer->FoundUnsupportedFeature();
+                return;
+            }
         }
     } else {
         fontParams.synBoldOnePixelOffset = 0;
@@ -2167,6 +2178,10 @@ gfxFont::Draw(const gfxTextRun *aTextRun, uint32_t aStart, uint32_t aEnd,
         cairo_matrix_t matrix;
         cairo_scaled_font_get_font_matrix(mScaledFont, &matrix);
         if (matrix.xy != 0) {
+            if (textDrawer) {
+                textDrawer->FoundUnsupportedFeature();
+            }
+
             // If this matrix applies a skew, which can happen when drawing
             // oblique fonts, we will set the DrawTarget matrix to apply the
             // skew. We'll need to move the glyphs by the inverse of the skew to

gfx/thebes/gfxTextRun.cpp

@@ -642,7 +642,9 @@ gfxTextRun::Draw(Range aRange, gfxPoint aPt, const DrawParams& aParams) const
 
     if (aParams.drawMode & DrawMode::GLYPH_FILL &&
         HasNonOpaqueNonTransparentColor(aParams.context, currentColor) &&
-        HasSyntheticBoldOrColor(this, aRange)) {
+        HasSyntheticBoldOrColor(this, aRange) &&
+        !aParams.context->GetTextDrawer()) {
+
         needToRestore = true;
         // Measure text; use the bounding box to determine the area we need
         // to buffer.

layout/generic/TextDrawTarget.h

@@ -160,19 +160,6 @@ public:
     size_t oldLength = glyphs.Length();
     glyphs.SetLength(oldLength + aBuffer.mNumGlyphs);
     PodCopy(glyphs.Elements() + oldLength, aBuffer.mGlyphs, aBuffer.mNumGlyphs);
-
-    // If there's a skew for synthetic italics we need to apply it, as the font
-    // code applies the inverse transformation to glyph positions in anticipation.
-    Matrix trans = GetTransform();
-    if (trans._21 != 0) {
-      Matrix skew = Matrix(1, trans._12,
-                           trans._21, 1,
-                           0, 0);
-      for (size_t i = oldLength; i < oldLength + aBuffer.mNumGlyphs; ++i) {
-        auto position = &glyphs[i].mPosition;
-        *position = skew.TransformPoint(*position);
-      }
-    }
   }
 
   void