Remove unused CreateError histograms for shared memory.

Bug: 1053139
Change-Id: Ie9cec438ebfcfe99d1068fec9c89a969e958dd1e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2108801Reviewed-by: Erik Chen <erikchen@chromium.org>
Reviewed-by: Alex Ilin <alexilin@chromium.org>
Reviewed-by: Nasko Oskov <nasko@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Commit-Queue: Brian White <bcwhite@chromium.org>
Cr-Commit-Position: refs/heads/master@{#752014}

base/memory/platform_shared_memory_region_android.cc

@@ -23,11 +23,6 @@ namespace subtle {
 
 namespace {
 
-// Emits UMA metrics about encountered errors.
-void LogCreateError(PlatformSharedMemoryRegion::CreateError error) {
-  UMA_HISTOGRAM_ENUMERATION("SharedMemory.CreateError", error);
-}
-
 int GetAshmemRegionProtectionMask(int fd) {
   int prot = ashmem_get_prot_region(fd);
   if (prot < 0) {
@@ -145,7 +140,6 @@ bool PlatformSharedMemoryRegion::MapAtInternal(off_t offset,
 PlatformSharedMemoryRegion PlatformSharedMemoryRegion::Create(Mode mode,
                                                               size_t size) {
   if (size == 0) {
-    LogCreateError(PlatformSharedMemoryRegion::CreateError::SIZE_ZERO);
     return {};
   }
 
@@ -154,7 +148,6 @@ PlatformSharedMemoryRegion PlatformSharedMemoryRegion::Create(Mode mode,
   size_t rounded_size = bits::Align(size, GetPageSize());
   if (rounded_size < size ||
       rounded_size > static_cast<size_t>(std::numeric_limits<int>::max())) {
-    LogCreateError(PlatformSharedMemoryRegion::CreateError::SIZE_TOO_LARGE);
     return {};
   }
 
@@ -166,8 +159,6 @@ PlatformSharedMemoryRegion PlatformSharedMemoryRegion::Create(Mode mode,
   int fd = ashmem_create_region(
       SharedMemoryTracker::GetDumpNameForTracing(guid).c_str(), rounded_size);
   if (fd < 0) {
-    LogCreateError(
-        PlatformSharedMemoryRegion::CreateError::CREATE_FILE_MAPPING_FAILURE);
     DPLOG(ERROR) << "ashmem_create_region failed";
     return {};
   }
@@ -175,13 +166,10 @@ PlatformSharedMemoryRegion PlatformSharedMemoryRegion::Create(Mode mode,
   ScopedFD scoped_fd(fd);
   int err = ashmem_set_prot_region(scoped_fd.get(), PROT_READ | PROT_WRITE);
   if (err < 0) {
-    LogCreateError(
-        PlatformSharedMemoryRegion::CreateError::REDUCE_PERMISSIONS_FAILURE);
     DPLOG(ERROR) << "ashmem_set_prot_region failed";
     return {};
   }
 
-  LogCreateError(PlatformSharedMemoryRegion::CreateError::SUCCESS);
   return PlatformSharedMemoryRegion(std::move(scoped_fd), mode, size, guid);
 }
 

base/memory/platform_shared_memory_region_mac.cc

@@ -21,13 +21,6 @@ namespace subtle {
 
 namespace {
 
-void LogCreateError(PlatformSharedMemoryRegion::CreateError error,
-                    kern_return_t mac_error) {
-  UMA_HISTOGRAM_ENUMERATION("SharedMemory.CreateError", error);
-  if (mac_error != KERN_SUCCESS)
-    UmaHistogramSparse("SharedMemory.CreateMacError", mac_error);
-}
-
 }  // namespace
 
 // static
@@ -165,12 +158,10 @@ bool PlatformSharedMemoryRegion::MapAtInternal(off_t offset,
 PlatformSharedMemoryRegion PlatformSharedMemoryRegion::Create(Mode mode,
                                                               size_t size) {
   if (size == 0) {
-    LogCreateError(CreateError::SIZE_ZERO, KERN_SUCCESS);
     return {};
   }
 
   if (size > static_cast<size_t>(std::numeric_limits<int>::max())) {
-    LogCreateError(CreateError::SIZE_TOO_LARGE, KERN_SUCCESS);
     return {};
   }
 
@@ -185,14 +176,11 @@ PlatformSharedMemoryRegion PlatformSharedMemoryRegion::Create(Mode mode,
       MAP_MEM_NAMED_CREATE | VM_PROT_READ | VM_PROT_WRITE,
       mac::ScopedMachSendRight::Receiver(named_right).get(),
       MACH_PORT_NULL);  // Parent handle.
-  if (kr != KERN_SUCCESS)
-    LogCreateError(CreateError::CREATE_FILE_MAPPING_FAILURE, kr);
   // Crash as soon as shm allocation fails to debug the issue
   // https://crbug.com/872237.
   MACH_CHECK(kr == KERN_SUCCESS, kr) << "mach_make_memory_entry_64";
   DCHECK_GE(vm_size, size);
 
-  LogCreateError(CreateError::SUCCESS, KERN_SUCCESS);
   return PlatformSharedMemoryRegion(std::move(named_right), mode, size,
                                     UnguessableToken::Create());
 }

base/memory/platform_shared_memory_region_posix.cc

@@ -18,12 +18,6 @@ namespace subtle {
 
 namespace {
 
-#if !defined(OS_NACL)
-void LogCreateError(PlatformSharedMemoryRegion::CreateError error) {
-  UMA_HISTOGRAM_ENUMERATION("SharedMemory.CreateError", error);
-}
-#endif
-
 struct ScopedPathUnlinkerTraits {
   static const FilePath* InvalidValue() { return nullptr; }
 
@@ -219,12 +213,10 @@ PlatformSharedMemoryRegion PlatformSharedMemoryRegion::Create(Mode mode,
   return {};
 #else
   if (size == 0) {
-    LogCreateError(PlatformSharedMemoryRegion::CreateError::SIZE_ZERO);
     return {};
   }
 
   if (size > static_cast<size_t>(std::numeric_limits<int>::max())) {
-    LogCreateError(PlatformSharedMemoryRegion::CreateError::SIZE_TOO_LARGE);
     return {};
   }
 
@@ -246,8 +238,6 @@ PlatformSharedMemoryRegion PlatformSharedMemoryRegion::Create(Mode mode,
           false /* executable */,
 #endif
           &directory)) {
-    LogCreateError(
-        PlatformSharedMemoryRegion::CreateError::GET_SHMEM_TEMP_DIR_FAILURE);
     return {};
   }
 
@@ -256,8 +246,6 @@ PlatformSharedMemoryRegion PlatformSharedMemoryRegion::Create(Mode mode,
   File shm_file(fd.release());
 
   if (!shm_file.IsValid()) {
-    LogCreateError(
-        PlatformSharedMemoryRegion::CreateError::CREATE_FILE_MAPPING_FAILURE);
     PLOG(ERROR) << "Creating shared memory in " << path.value() << " failed";
     FilePath dir = path.DirName();
     if (access(dir.value().c_str(), W_OK | X_OK) < 0) {
@@ -280,43 +268,35 @@ PlatformSharedMemoryRegion PlatformSharedMemoryRegion::Create(Mode mode,
     // Also open as readonly so that we can ConvertToReadOnly().
     readonly_fd.reset(HANDLE_EINTR(open(path.value().c_str(), O_RDONLY)));
     if (!readonly_fd.is_valid()) {
-      LogCreateError(
-          PlatformSharedMemoryRegion::CreateError::REDUCE_PERMISSIONS_FAILURE);
       DPLOG(ERROR) << "open(\"" << path.value() << "\", O_RDONLY) failed";
       return {};
     }
   }
 
   if (!AllocateFileRegion(&shm_file, 0, size)) {
-    LogCreateError(
-        PlatformSharedMemoryRegion::CreateError::ALLOCATE_FILE_REGION_FAILURE);
     return {};
   }
 
   if (readonly_fd.is_valid()) {
     stat_wrapper_t shm_stat;
     if (File::Fstat(shm_file.GetPlatformFile(), &shm_stat) != 0) {
-      LogCreateError(PlatformSharedMemoryRegion::CreateError::FSTAT_FAILURE);
       DPLOG(ERROR) << "fstat(fd) failed";
       return {};
     }
 
     stat_wrapper_t readonly_stat;
     if (File::Fstat(readonly_fd.get(), &readonly_stat) != 0) {
-      LogCreateError(PlatformSharedMemoryRegion::CreateError::FSTAT_FAILURE);
       DPLOG(ERROR) << "fstat(readonly_fd) failed";
       return {};
     }
 
     if (shm_stat.st_dev != readonly_stat.st_dev ||
         shm_stat.st_ino != readonly_stat.st_ino) {
-      LogCreateError(PlatformSharedMemoryRegion::CreateError::INODES_MISMATCH);
       LOG(ERROR) << "Writable and read-only inodes don't match; bailing";
       return {};
     }
   }
 
-  LogCreateError(PlatformSharedMemoryRegion::CreateError::SUCCESS);
   return PlatformSharedMemoryRegion(
       {ScopedFD(shm_file.TakePlatformFile()), std::move(readonly_fd)}, mode,
       size, UnguessableToken::Create());

base/memory/platform_shared_memory_region_win.cc

@@ -24,15 +24,6 @@ namespace subtle {
 
 namespace {
 
-// Emits UMA metrics about encountered errors. Pass zero (0) for |winerror|
-// if there is no associated Windows error.
-void LogError(PlatformSharedMemoryRegion::CreateError error, DWORD winerror) {
-  UMA_HISTOGRAM_ENUMERATION("SharedMemory.CreateError", error);
-  static_assert(ERROR_SUCCESS == 0, "Windows error code changed!");
-  if (winerror != ERROR_SUCCESS)
-    UmaHistogramSparse("SharedMemory.CreateWinError", winerror);
-}
-
 typedef enum _SECTION_INFORMATION_CLASS {
   SectionBasicInformation,
 } SECTION_INFORMATION_CLASS;
@@ -96,9 +87,6 @@ HANDLE CreateFileMappingWithReducedPermissions(SECURITY_ATTRIBUTES* sa,
   HANDLE h = CreateFileMapping(INVALID_HANDLE_VALUE, sa, PAGE_READWRITE, 0,
                                static_cast<DWORD>(rounded_size), name);
   if (!h) {
-    LogError(
-        PlatformSharedMemoryRegion::CreateError::CREATE_FILE_MAPPING_FAILURE,
-        GetLastError());
     return nullptr;
   }
 
@@ -111,9 +99,6 @@ HANDLE CreateFileMappingWithReducedPermissions(SECURITY_ATTRIBUTES* sa,
   DCHECK(rv);
 
   if (!success) {
-    LogError(
-        PlatformSharedMemoryRegion::CreateError::REDUCE_PERMISSIONS_FAILURE,
-        GetLastError());
     return nullptr;
   }
 
@@ -237,7 +222,6 @@ PlatformSharedMemoryRegion PlatformSharedMemoryRegion::Create(Mode mode,
   // per mapping on average.
   static const size_t kSectionSize = 65536;
   if (size == 0) {
-    LogError(CreateError::SIZE_ZERO, 0);
     return {};
   }
 
@@ -245,7 +229,6 @@ PlatformSharedMemoryRegion PlatformSharedMemoryRegion::Create(Mode mode,
   size_t rounded_size = bits::Align(size, kSectionSize);
   if (rounded_size < size ||
       rounded_size > static_cast<size_t>(std::numeric_limits<int>::max())) {
-    LogError(CreateError::SIZE_TOO_LARGE, 0);
     return {};
   }
 
@@ -256,15 +239,12 @@ PlatformSharedMemoryRegion PlatformSharedMemoryRegion::Create(Mode mode,
   ACL dacl;
   SECURITY_DESCRIPTOR sd;
   if (!InitializeAcl(&dacl, sizeof(dacl), ACL_REVISION)) {
-    LogError(CreateError::INITIALIZE_ACL_FAILURE, GetLastError());
     return {};
   }
   if (!InitializeSecurityDescriptor(&sd, SECURITY_DESCRIPTOR_REVISION)) {
-    LogError(CreateError::INITIALIZE_SECURITY_DESC_FAILURE, GetLastError());
     return {};
   }
   if (!SetSecurityDescriptorDacl(&sd, TRUE, &dacl, FALSE)) {
-    LogError(CreateError::SET_SECURITY_DESC_FAILURE, GetLastError());
     return {};
   }
 
@@ -294,11 +274,9 @@ PlatformSharedMemoryRegion PlatformSharedMemoryRegion::Create(Mode mode,
   win::ScopedHandle scoped_h(h);
   // Check if the shared memory pre-exists.
   if (GetLastError() == ERROR_ALREADY_EXISTS) {
-    LogError(CreateError::ALREADY_EXISTS, ERROR_ALREADY_EXISTS);
     return {};
   }
 
-  LogError(CreateError::SUCCESS, ERROR_SUCCESS);
   return PlatformSharedMemoryRegion(std::move(scoped_h), mode, size,
                                     UnguessableToken::Create());
 }

tools/metrics/histograms/histograms.xml

@@ -148674,6 +148674,10 @@ should be kept until we remove incident reporting. -->
 
 <histogram name="SharedMemory.CreateError" enum="SharedMemoryCreateError"
     expires_after="M81">
+  <obsolete>
+    Not accessed in months. Primary error was CREATE_FILE_MAPPING_FAILURE by
+    far. Removed 2020-03.
+  </obsolete>
   <owner>erikchen@chromium.org</owner>
   <owner>alexilin@chromium.org</owner>
   <summary>
@@ -148686,6 +148690,9 @@ should be kept until we remove incident reporting. -->
 
 <histogram name="SharedMemory.CreateMacError" enum="MachKernReturn"
     expires_after="M85">
+  <obsolete>
+    Not accessed in months and no data reported for it at all. Removed 2020-03.
+  </obsolete>
   <owner>alexilin@chromium.org</owner>
   <summary>
     Emitted each time a shared memory region could not be created due to a
@@ -148696,6 +148703,9 @@ should be kept until we remove incident reporting. -->
 
 <histogram name="SharedMemory.CreateWinError" enum="WinGetLastError"
     expires_after="M82">
+  <obsolete>
+    Not accessed in months. Primary error was #1455 by far. Removed 2020-03.
+  </obsolete>
   <owner>bcwhite@chromium.org</owner>
   <summary>
     A histogram entry is emitted each time a shared memory object could not be