gpu: Increase Skia resource cache item limit

Increase Skia GrContext resource cache item limit.
MS Chalkboard test case has 2400 paths. The old limit
would cause path cache trashing when the scene was
played back.

Fixes slowness on
smoothness.gpu_rasterization.tough_path_rendering_cases
on hardware that has GL API level path rendering enabled.
CQ_INCLUDE_TRYBOTS=tryserver.chromium.linux:linux_optional_gpu_tests_rel;tryserver.chromium.mac:mac_optional_gpu_tests_rel;tryserver.chromium.win:win_optional_gpu_tests_rel

Review-Url: https://codereview.chromium.org/2020013002
Cr-Commit-Position: refs/heads/master@{#397379}

gpu/skia_bindings/grcontext_for_gles2_interface.cc

@@ -29,7 +29,7 @@ GrContextForGLES2Interface::GrContextForGLES2Interface(
   if (gr_context_) {
     // The limit of the number of GPU resources we hold in the GrContext's
     // GPU cache.
-    static const int kMaxGaneshResourceCacheCount = 2048;
+    static const int kMaxGaneshResourceCacheCount = 8196;
     // The limit of the bytes allocated toward GPU resources in the GrContext's
     // GPU cache.
     static const size_t kMaxGaneshResourceCacheBytes = 96 * 1024 * 1024;