Work on getting things built with -Wimplicit-fallthrough. This CL was uploaded by git cl split.

Bug: 177475
R=vollick@chromium.org

Cq-Include-Trybots: master.tryserver.chromium.android:android_optional_gpu_tests_rel
Change-Id: Ib6d33bcaf7f42728bd996b1e7bfac42033a293fd
Reviewed-on: https://chromium-review.googlesource.com/889786Reviewed-by: Ian Vollick <vollick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#532236}

components/viz/common/gl_helper_scaling.cc

@@ -653,6 +653,7 @@ void GLHelperScaling::ConvertScalerOpsToScalerStages(
           switch (x_ops->size()) {
             case 0:
               NOTREACHED();
+              break;
             case 1:
               if (x_ops->front().scale_factor == 3) {
                 current_shader = SHADER_BILINEAR3;

components/viz/service/display/scoped_render_pass_texture.cc

@@ -108,7 +108,7 @@ void ScopedRenderPassTexture::BindForSampling() {
       DCHECK(context_provider_->ContextCapabilities().texture_npot);
       gl->GenerateMipmap(GL_TEXTURE_2D);
       mipmap_state_ = VALID;
-    // fall-through
+      FALLTHROUGH;
     case VALID:
       gl->TexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER,
                         GL_LINEAR_MIPMAP_LINEAR);

components/viz/service/display/shader.cc

@@ -348,7 +348,7 @@ std::string VertexShader::GetShaderString() const {
         break;
       case TEX_COORD_TRANSFORM_TRANSLATED_VEC4:
         SRC("texCoord = texCoord + vec2(0.5);");
-      // Fall through...
+        FALLTHROUGH;
       case TEX_COORD_TRANSFORM_VEC4:
         if (use_uniform_arrays_) {
           HDR("uniform TexCoordPrecision vec4 vertexTexTransform[NUM_QUADS];");