Add histograms for LUMINANCE_F16 and R16_EXT.

Add and record UMA for R16_EXT and LUMINANCE_F16.
We add the UMA for both these formats as it would be nice to get
rid of one or the other eventually.

Bug: 759456
Cq-Include-Trybots: master.tryserver.chromium.android:android_optional_gpu_tests_rel;master.tryserver.chromium.linux:linux_optional_gpu_tests_rel;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.win:win_optional_gpu_tests_rel
Change-Id: Iaee25dff684312229ceb408dbfde76985e566629
Reviewed-on: https://chromium-review.googlesource.com/635463
Commit-Queue: Rijubrata Bhaumik <rijubrata.bhaumik@intel.com>
Reviewed-by: Fredrik Hubinette <hubbe@chromium.org>
Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Reviewed-by: Antoine Labour <piman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#502795}

gpu/command_buffer/service/feature_info.cc

@@ -177,6 +177,35 @@ bool IsWebGLDrawBuffersSupported(bool webglCompatibilityContext,
 
 }  // anonymous namespace.
 
+namespace {
+
+enum GpuTextureResultR16_L16 {
+  // Values synced with 'GpuTextureResultR16_L16' in
+  // src/tools/metrics/histograms/histograms.xml
+  kHaveNone = 0,
+  kHaveR16 = 1,
+  kHaveL16 = 2,
+  kHaveR16AndL16 = 3,
+  kMax = kHaveR16AndL16
+};
+
+// TODO(riju): For UMA, remove after crbug.com/759456 is resolved.
+bool g_r16_is_present;
+bool g_l16_is_present;
+
+GpuTextureResultR16_L16 GpuTextureUMAHelper() {
+  if (g_r16_is_present && g_l16_is_present) {
+    return GpuTextureResultR16_L16::kHaveR16AndL16;
+  } else if (g_r16_is_present) {
+    return GpuTextureResultR16_L16::kHaveR16;
+  } else if (g_l16_is_present) {
+    return GpuTextureResultR16_L16::kHaveL16;
+  }
+  return GpuTextureResultR16_L16::kHaveNone;
+}
+
+}  // anonymous namespace.
+
 FeatureInfo::FeatureFlags::FeatureFlags() {}
 
 FeatureInfo::FeatureInfo() {
@@ -1298,6 +1327,7 @@ void FeatureInfo::InitializeFeatures() {
   if (gl_version_info_->is_desktop_core_profile ||
       gl::HasExtension(extensions, "GL_EXT_texture_norm16")) {
     feature_flags_.ext_texture_norm16 = true;
+    g_r16_is_present = true;
     AddExtensionString("GL_EXT_texture_norm16");
 
     // Note: EXT_texture_norm16 is not exposed through WebGL API so we validate
@@ -1308,6 +1338,10 @@ void FeatureInfo::InitializeFeatures() {
     validators_.texture_unsized_internal_format.AddValue(GL_RED_EXT);
   }
 
+  UMA_HISTOGRAM_ENUMERATION(
+      "GPU.TextureR16Ext_LuminanceF16", GpuTextureUMAHelper(),
+      static_cast<int>(GpuTextureResultR16_L16::kMax) + 1);
+
   bool has_opengl_dual_source_blending =
       gl_version_info_->IsAtLeastGL(3, 3) ||
       (gl_version_info_->IsAtLeastGL(3, 2) &&
@@ -1618,6 +1652,9 @@ void FeatureInfo::InitializeFloatAndHalfFloatFeatures(
           GL_LUMINANCE_ALPHA16F_EXT);
     }
   }
+
+  g_l16_is_present =
+      enable_texture_half_float && feature_flags_.ext_texture_storage;
 }
 
 bool FeatureInfo::IsES3Capable() const {

tools/metrics/histograms/enums.xml

@@ -19466,6 +19466,17 @@ uploading your change for review.  These are checked by presubmit scripts.
   <int value="3" label="active, was active"/>
 </enum>
 
+<enum name="GpuTextureResultR16_L16">
+  <summary>
+    Keeps track of how many users have R16_EXT or/and LUMINANCE_F16, and also
+    how many have none of the two.
+  </summary>
+  <int value="0" label="HAVE_NONE"/>
+  <int value="1" label="HAVE_R16"/>
+  <int value="2" label="HAVE_L16"/>
+  <int value="3" label="HAVE_R16_AND_L16"/>
+</enum>
+
 <enum name="GPUThreeDAPIInfoBarDismissal">
   <summary>Results of user actions when a 3D API info bar is raised.</summary>
   <int value="0" label="Ignored"/>

tools/metrics/histograms/histograms.xml

@@ -25744,6 +25744,16 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="GPU.TextureR16Ext_LuminanceF16" enum="GpuTextureResultR16_L16">
+  <owner>hubbe@chromium.org</owner>
+  <owner>rijubrata.bhaumik@intel.com</owner>
+  <owner>media-dev@chromium.org</owner>
+  <summary>
+    Whether LUMINANCE_F16 and/or R16_EXT texture support is available. Recorded
+    each time a new context group is initialized and extensions are detected.
+  </summary>
+</histogram>
+
 <histogram name="GPU.TextureRG" enum="BooleanAvailable">
   <owner>reveman@chromium.org</owner>
   <summary>