Selection Handles Fix
Issue
On Android, text selection handles were not visible when an input field's
line-height exceeded its height.
The fix required two CLs: one for the blink paint path (merged) and one
for the CC compositor path (pending).
Blink Visual Comparison (Non-Composited)
Before (Bug)
Selection handles not visible
After (Fixed)
Selection handles correctly visible
CC Visual Comparison (Composited Layers)
Before (Bug)
Composited input - handles not visible
After (Fixed)
Composited input - handles correctly visible
Downloads (x86 emulator)
Install via adb install -r <file>.apk, then open sampler.html on device.
patched.apk -- Blink paint-path fix + CC compositor-path fix. All test cases should show handles.
unpatched.apk -- Blink paint-path fix only. Composited inputs (will-change, translateZ) may still hide handles.
Two Code Paths
Blink Paint path (non-composited)
PaintedSelectionBoundToLayerSelectionBound in
paint_chunks_to_cc_layer.cc.
Fixed by CL 7596201:
uses the full edge bounding rect instead of a single point near edge_end.
CC Compositor path (composited layers)
ComputeViewportSelectionBound in
cc/trees/layer_tree_impl.cc.
Follow-up CL: when the point near edge_end misses, also checks a point
near edge_start. Gated behind kCCSelectionEdgeVisibilityUsesFullEdge
in cc/base/features.h.
Composited layers are triggered by will-change: transform,
transform: translateZ(0), hardware-accelerated scrolling, etc.
Unit Tests
# Blink-side (CL 7596201, merged)
tools/autotest.py -C out/Default \
--gtest_filter="SelectionBoundsRecorderTest.Bounds*" \
third_party/blink/renderer/core/paint/selection_bounds_recorder_test.cc
# CC-side (follow-up CL)
./out/Default/cc_unittests \
--gtest_filter="*SelectionBoundsVisibleWithPartialEdgeOverflow*"