Fix float-cast-overflow in IndividualCharacterAdvances

Advances should be store as doubles, but the previous code
was using a float as a part of their computation.

Bug: 880169
Change-Id: I47fd70bf947c9b1e0fdb827eba69108bd938a72a
Reviewed-on: https://chromium-review.googlesource.com/1213516Reviewed-by: Stephen White <senorblanco@chromium.org>
Commit-Queue: David Quiroz Marin <davidqu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#590010}

third_party/blink/renderer/platform/fonts/shaping/shape_result_buffer.cc

@@ -200,7 +200,7 @@ Vector<CharacterRange> ShapeResultBuffer::IndividualCharacterRanges(
 }
 
 void ShapeResultBuffer::AddRunInfoAdvances(const ShapeResult::RunInfo& run_info,
-                                           float offset,
+                                           double offset,
                                            Vector<double>& advances) {
   const unsigned num_glyphs = run_info.glyph_data_.size();
   const unsigned num_chars = run_info.num_characters_;
@@ -254,7 +254,7 @@ Vector<double> ShapeResultBuffer::IndividualCharacterAdvances(
     float total_width) const {
   unsigned character_offset = 0;
   Vector<double> advances;
-  float current_x = direction == TextDirection::kRtl ? total_width : 0;
+  double current_x = direction == TextDirection::kRtl ? total_width : 0;
 
   for (const scoped_refptr<const ShapeResult> result : results_) {
     unsigned run_count = result->runs_.size();

third_party/blink/renderer/platform/fonts/shaping/shape_result_buffer.h

@@ -72,7 +72,7 @@ class PLATFORM_EXPORT ShapeResultBuffer {
       unsigned to);
 
   static void AddRunInfoAdvances(const ShapeResult::RunInfo& run_info,
-                                 float offset,
+                                 double offset,
                                  Vector<double>& advances);
   static void AddRunInfoRanges(const ShapeResult::RunInfo&,
                                float offset,