Stop recording Android.ArmFpu

Chrome on Android/ARM relies on NEON. Counts for "No NEON support" are
extremely low, and hence not useful overall.

Bug: 489738
Change-Id: Ic96cdc4bc9274400d720b7e8f5c33b6887d04692
Reviewed-on: https://chromium-review.googlesource.com/c/1449659Reviewed-by: Brian White <bcwhite@chromium.org>
Commit-Queue: Egor Pasko <pasko@chromium.org>
Cr-Commit-Position: refs/heads/master@{#628332}

chrome/browser/metrics/chrome_browser_main_extra_parts_metrics.cc

@@ -173,14 +173,6 @@ enum UMATouchEventFeatureDetectionState {
   UMA_TOUCH_EVENT_FEATURE_DETECTION_STATE_COUNT
 };
 
-#if defined(OS_ANDROID) && defined(__arm__)
-enum UMAAndroidArmFpu {
-  UMA_ANDROID_ARM_FPU_VFPV3_D16,  // The ARM CPU only supports vfpv3-d16.
-  UMA_ANDROID_ARM_FPU_NEON,       // The Arm CPU supports NEON.
-  UMA_ANDROID_ARM_FPU_COUNT
-};
-#endif  // defined(OS_ANDROID) && defined(__arm__)
-
 void RecordMicroArchitectureStats() {
 #if defined(ARCH_CPU_X86_FAMILY)
   base::CPU cpu;
@@ -188,19 +180,6 @@ void RecordMicroArchitectureStats() {
   UMA_HISTOGRAM_ENUMERATION("Platform.IntelMaxMicroArchitecture", arch,
                             base::CPU::MAX_INTEL_MICRO_ARCHITECTURE);
 #endif  // defined(ARCH_CPU_X86_FAMILY)
-#if defined(OS_ANDROID) && defined(__arm__)
-  // Detect NEON support.
-  // TODO(fdegans): Remove once non-NEON support has been removed.
-  if (android_getCpuFeatures() & ANDROID_CPU_ARM_FEATURE_NEON) {
-    UMA_HISTOGRAM_ENUMERATION("Android.ArmFpu",
-                              UMA_ANDROID_ARM_FPU_NEON,
-                              UMA_ANDROID_ARM_FPU_COUNT);
-  } else {
-    UMA_HISTOGRAM_ENUMERATION("Android.ArmFpu",
-                              UMA_ANDROID_ARM_FPU_VFPV3_D16,
-                              UMA_ANDROID_ARM_FPU_COUNT);
-  }
-#endif  // defined(OS_ANDROID) && defined(__arm__)
   base::UmaHistogramSparse("Platform.LogicalCpuCount",
                            base::SysInfo::NumberOfProcessors());
 }

tools/metrics/histograms/histograms.xml

@@ -1303,6 +1303,9 @@ uploading your change for review.
 </histogram>
 
 <histogram name="Android.ArmFpu" enum="AndroidArmFpu">
+  <obsolete>
+    Removed 2019-01: New releases of Chrome+Android+ARM rely on NEON support.
+  </obsolete>
   <owner>fdegans@chromium.org</owner>
   <summary>
     Reports the FPU capabilities of the Android ARM device. This is recorded