Revert of Pass both 32 and 64 bit snapshot and natives fds to child processes. (patchset #3 id:40001 of https://codereview.chromium.org/1665513002/ )

Reason for revert:
Added a static initializer: https://build.chromium.org/p/chromium/builders/Linux/builds/71576
# v8_initializer.cc _GLOBAL__sub_I_v8_initializer.cc+0xf
# v8_initializer.cc __cxa_atexit@plt [registers a dtor to run at exit]

Original issue's description:
> Pass both 32 and 64 bit snapshot and natives fds to child processes.
>
> Child processes are in the best position to determine which files
> to use, therefore it is simplest just to provide both 32 and 64
> bit versions from the parent.
>
> BUG=581380,455699
>
> Committed: https://crrev.com/c560d75783aca05249092dd11503b53f7b631be1
> Cr-Commit-Position: refs/heads/master@{#374371}

TBR=jochen@chromium.org,torne@chromium.org,tobiasjs@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=581380,455699

Review URL: https://codereview.chromium.org/1681003003

Cr-Commit-Position: refs/heads/master@{#374380}

7 files changed, 56 insertions, 160 deletions

diff --git a/android_webview/lib/DEPS b/android_webview/lib/DEPS
index 572fe0c..e46fa53 100644
--- a/android_webview/lib/DEPS
+++ b/android_webview/lib/DEPS
@@ -3,7 +3,6 @@ include_rules = [
   "+components",  # For jni registers.
   "+content/public",
   "+gin/public",
-  "+gin/v8_initializer.h",
   "+media/base/media_switches.h",  # For media command line switches.
   "+ui/events/gesture_detection",
   "+ui/gl",
diff --git a/android_webview/lib/main/aw_main_delegate.cc b/android_webview/lib/main/aw_main_delegate.cc
index e858652..e0025fe 100644
--- a/android_webview/lib/main/aw_main_delegate.cc
+++ b/android_webview/lib/main/aw_main_delegate.cc
@@ -34,7 +34,6 @@
 #include "content/public/common/content_descriptors.h"
 #include "content/public/common/content_switches.h"
 #include "gin/public/isolate_holder.h"
-#include "gin/v8_initializer.h"
 #include "gpu/command_buffer/client/gl_in_process_context.h"
 #include "gpu/command_buffer/service/gpu_switches.h"
 #include "media/base/media_switches.h"
@@ -118,19 +117,24 @@ bool AwMainDelegate::BasicStartupComplete(int* exit_code) {
   if (cl->GetSwitchValueASCII(switches::kProcessType).empty()) {
     // Browser process (no type specified).
 
-    base::android::RegisterApkAssetWithGlobalDescriptors(
-        kV8NativesDataDescriptor32,
-        gin::V8Initializer::GetNativesFilePath(true).AsUTF8Unsafe());
-    base::android::RegisterApkAssetWithGlobalDescriptors(
-        kV8SnapshotDataDescriptor32,
-        gin::V8Initializer::GetSnapshotFilePath(true).AsUTF8Unsafe());
-
-    base::android::RegisterApkAssetWithGlobalDescriptors(
-        kV8NativesDataDescriptor64,
-        gin::V8Initializer::GetNativesFilePath(false).AsUTF8Unsafe());
-    base::android::RegisterApkAssetWithGlobalDescriptors(
-        kV8SnapshotDataDescriptor64,
-        gin::V8Initializer::GetSnapshotFilePath(false).AsUTF8Unsafe());
+    // This code is needed to be able to mmap the V8 snapshot directly from
+    // the WebView .apk using architecture-specific names.
+    // This needs to be here so that it gets to run before the code in
+    // content_main_runner that reads these values tries to do so.
+#ifdef __LP64__
+    const char kNativesFileName[] = "assets/natives_blob_64.bin";
+    const char kSnapshotFileName[] = "assets/snapshot_blob_64.bin";
+#else
+    const char kNativesFileName[] = "assets/natives_blob_32.bin";
+    const char kSnapshotFileName[] = "assets/snapshot_blob_32.bin";
+#endif // __LP64__
+    // TODO(gsennton) we should use
+    // gin::IsolateHolder::kNativesFileName/kSnapshotFileName
+    // here when those files have arch specific names http://crbug.com/455699
+    CHECK(base::android::RegisterApkAssetWithGlobalDescriptors(
+        kV8NativesDataDescriptor, kNativesFileName));
+    CHECK(base::android::RegisterApkAssetWithGlobalDescriptors(
+        kV8SnapshotDataDescriptor, kSnapshotFileName));
   }
 
   if (cl->HasSwitch(switches::kWebViewSandboxedRenderer)) {
diff --git a/content/app/content_main_runner.cc b/content/app/content_main_runner.cc
index 59efad3..e8d31b0 100644
--- a/content/app/content_main_runner.cc
+++ b/content/app/content_main_runner.cc
@@ -142,16 +142,6 @@ base::LazyInstance<ContentUtilityClient>
     g_empty_content_utility_client = LAZY_INSTANCE_INITIALIZER;
 #endif  // !OS_IOS && !CHROME_MULTIPLE_DLL_BROWSER
 
-#if defined(V8_USE_EXTERNAL_STARTUP_DATA) && defined(OS_ANDROID)
-#if defined __LP64__
-#define kV8NativesDataDescriptor kV8NativesDataDescriptor64
-#define kV8SnapshotDataDescriptor kV8SnapshotDataDescriptor64
-#else
-#define kV8NativesDataDescriptor kV8NativesDataDescriptor32
-#define kV8SnapshotDataDescriptor kV8SnapshotDataDescriptor32
-#endif
-#endif
-
 #if defined(OS_POSIX) && !defined(OS_IOS)
 
 // Setup signal-handling state: resanitize most signals, ignore SIGPIPE.
diff --git a/content/browser/child_process_launcher.cc b/content/browser/child_process_launcher.cc
index e92554c..4398e2b 100644
--- a/content/browser/child_process_launcher.cc
+++ b/content/browser/child_process_launcher.cc
@@ -156,31 +156,6 @@ void LaunchOnLauncherThread(const NotifyCallback& callback,
 #endif
       );
 #if defined(V8_USE_EXTERNAL_STARTUP_DATA)
-  bool snapshot_loaded = false;
-#if defined(OS_ANDROID)
-  base::MemoryMappedFile::Region region;
-  auto maybe_register = [&region, &regions, &files_to_register](int key,
-                                                                int fd) {
-    if (fd != -1) {
-      files_to_register->Share(key, fd);
-      regions.insert(std::make_pair(key, region));
-    }
-  };
-  maybe_register(
-      kV8NativesDataDescriptor32,
-      gin::V8Initializer::GetOpenNativesFileForChildProcesses(&region, true));
-  maybe_register(
-      kV8NativesDataDescriptor64,
-      gin::V8Initializer::GetOpenNativesFileForChildProcesses(&region, false));
-  maybe_register(
-      kV8SnapshotDataDescriptor32,
-      gin::V8Initializer::GetOpenSnapshotFileForChildProcesses(&region, true));
-  maybe_register(
-      kV8SnapshotDataDescriptor64,
-      gin::V8Initializer::GetOpenSnapshotFileForChildProcesses(&region, false));
-
-  snapshot_loaded = true;
-#else
   base::PlatformFile natives_pf =
       gin::V8Initializer::GetOpenNativesFileForChildProcesses(
           &regions[kV8NativesDataDescriptor]);
@@ -194,15 +169,13 @@ void LaunchOnLauncherThread(const NotifyCallback& callback,
   // Failure to load the V8 snapshot is not necessarily an error. V8 can start
   // up (slower) without the snapshot.
   if (snapshot_pf != -1) {
-    snapshot_loaded = true;
     files_to_register->Share(kV8SnapshotDataDescriptor, snapshot_pf);
     regions.insert(std::make_pair(kV8SnapshotDataDescriptor, snapshot_region));
   }
-#endif
 
   if (process_type != switches::kZygoteProcess) {
     cmd_line->AppendSwitch(::switches::kV8NativesPassedByFD);
-    if (snapshot_loaded) {
+    if (snapshot_pf != -1) {
       cmd_line->AppendSwitch(::switches::kV8SnapshotPassedByFD);
     }
   }
diff --git a/content/public/common/content_descriptors.h b/content/public/common/content_descriptors.h
index 692b8bd..a3077cd 100644
--- a/content/public/common/content_descriptors.h
+++ b/content/public/common/content_descriptors.h
@@ -15,16 +15,9 @@ enum {
   kSandboxIPCChannel,  // https://chromium.googlesource.com/chromium/src/+/master/docs/linux_sandbox_ipc.md
 
 #if defined(V8_USE_EXTERNAL_STARTUP_DATA)
-#if defined(OS_ANDROID)
-  kV8NativesDataDescriptor32,
-  kV8SnapshotDataDescriptor32,
-  kV8NativesDataDescriptor64,
-  kV8SnapshotDataDescriptor64,
-#else
   kV8NativesDataDescriptor,
   kV8SnapshotDataDescriptor,
 #endif
-#endif
 
 #if defined(OS_ANDROID)
   kAndroidPropertyDescriptor,
diff --git a/gin/v8_initializer.cc b/gin/v8_initializer.cc
index 2233e3f..cfb3630 100644
--- a/gin/v8_initializer.cc
+++ b/gin/v8_initializer.cc
@@ -50,32 +50,19 @@ const base::PlatformFile kInvalidPlatformFile =
 // File handles intentionally never closed. Not using File here because its
 // Windows implementation guards against two instances owning the same
 // PlatformFile (which we allow since we know it is never freed).
-typedef std::map<const char*,
-                 std::pair<base::PlatformFile, base::MemoryMappedFile::Region>>
-    OpenedFileMap;
-OpenedFileMap g_opened_files;
-
-OpenedFileMap::mapped_type& GetOpenedFile(const char* file) {
-  if (g_opened_files.find(file) == g_opened_files.end()) {
-    g_opened_files[file] =
-        std::make_pair(kInvalidPlatformFile, base::MemoryMappedFile::Region());
-  }
-  return g_opened_files[file];
-}
+base::PlatformFile g_natives_pf = kInvalidPlatformFile;
+base::PlatformFile g_snapshot_pf = kInvalidPlatformFile;
+base::MemoryMappedFile::Region g_natives_region;
+base::MemoryMappedFile::Region g_snapshot_region;
 
 #if defined(OS_ANDROID)
-const char kNativesFileName64[] = "natives_blob_64.bin";
-const char kSnapshotFileName64[] = "snapshot_blob_64.bin";
-const char kNativesFileName32[] = "natives_blob_32.bin";
-const char kSnapshotFileName32[] = "snapshot_blob_32.bin";
-
-#if defined(__LP64__)
-#define kNativesFileName kNativesFileName64
-#define kSnapshotFileName kSnapshotFileName64
+#ifdef __LP64__
+const char kNativesFileName[] = "natives_blob_64.bin";
+const char kSnapshotFileName[] = "snapshot_blob_64.bin";
 #else
-#define kNativesFileName kNativesFileName32
-#define kSnapshotFileName kSnapshotFileName32
-#endif
+const char kNativesFileName[] = "natives_blob_32.bin";
+const char kSnapshotFileName[] = "snapshot_blob_32.bin";
+#endif // __LP64__
 
 #else  // defined(OS_ANDROID)
 const char kNativesFileName[] = "natives_blob.bin";
@@ -183,13 +170,16 @@ base::PlatformFile OpenV8File(const char* file_name,
   return file.TakePlatformFile();
 }
 
-static const OpenedFileMap::mapped_type OpenFileIfNecessary(
-    const char* file_name) {
-  OpenedFileMap::mapped_type& opened = GetOpenedFile(file_name);
-  if (opened.first == kInvalidPlatformFile) {
-    opened.first = OpenV8File(file_name, &opened.second);
+void OpenNativesFileIfNecessary() {
+  if (g_natives_pf == kInvalidPlatformFile) {
+    g_natives_pf = OpenV8File(kNativesFileName, &g_natives_region);
+  }
+}
+
+void OpenSnapshotFileIfNecessary() {
+  if (g_snapshot_pf == kInvalidPlatformFile) {
+    g_snapshot_pf = OpenV8File(kSnapshotFileName, &g_snapshot_region);
   }
-  return opened;
 }
 
 #if defined(V8_VERIFY_EXTERNAL_STARTUP_DATA)
@@ -246,14 +236,15 @@ enum LoadV8FileResult {
   V8_LOAD_MAX_VALUE
 };
 
-static LoadV8FileResult MapVerify(const OpenedFileMap::mapped_type& file_region,
+static LoadV8FileResult MapVerify(base::PlatformFile platform_file,
+                                  const base::MemoryMappedFile::Region& region,
 #if defined(V8_VERIFY_EXTERNAL_STARTUP_DATA)
                                   const unsigned char* fingerprint,
 #endif
                                   base::MemoryMappedFile** mmapped_file_out) {
-  if (file_region.first == kInvalidPlatformFile)
+  if (platform_file == kInvalidPlatformFile)
     return V8_LOAD_FAILED_OPEN;
-  if (!MapV8File(file_region.first, file_region.second, mmapped_file_out))
+  if (!MapV8File(platform_file, region, mmapped_file_out))
     return V8_LOAD_FAILED_MAP;
 #if defined(V8_VERIFY_EXTERNAL_STARTUP_DATA)
   if (!VerifyV8StartupFile(mmapped_file_out, fingerprint))
@@ -267,8 +258,8 @@ void V8Initializer::LoadV8Snapshot() {
   if (g_mapped_snapshot)
     return;
 
-  OpenFileIfNecessary(kSnapshotFileName);
-  LoadV8FileResult result = MapVerify(GetOpenedFile(kSnapshotFileName),
+  OpenSnapshotFileIfNecessary();
+  LoadV8FileResult result = MapVerify(g_snapshot_pf, g_snapshot_region,
 #if defined(V8_VERIFY_EXTERNAL_STARTUP_DATA)
                                       g_snapshot_fingerprint,
 #endif
@@ -283,8 +274,8 @@ void V8Initializer::LoadV8Natives() {
   if (g_mapped_natives)
     return;
 
-  OpenFileIfNecessary(kNativesFileName);
-  LoadV8FileResult result = MapVerify(GetOpenedFile(kNativesFileName),
+  OpenNativesFileIfNecessary();
+  LoadV8FileResult result = MapVerify(g_natives_pf, g_natives_region,
 #if defined(V8_VERIFY_EXTERNAL_STARTUP_DATA)
                                       g_natives_fingerprint,
 #endif
@@ -320,8 +311,8 @@ void V8Initializer::LoadV8SnapshotFromFD(base::PlatformFile snapshot_pf,
     result = V8_LOAD_FAILED_VERIFY;
 #endif  // V8_VERIFY_EXTERNAL_STARTUP_DATA
   if (result == V8_LOAD_SUCCESS) {
-    g_opened_files[kSnapshotFileName] =
-        std::make_pair(snapshot_pf, snapshot_region);
+    g_snapshot_pf = snapshot_pf;
+    g_snapshot_region = snapshot_region;
   }
   UMA_HISTOGRAM_ENUMERATION("V8.Initializer.LoadV8Snapshot.Result", result,
                             V8_LOAD_MAX_VALUE);
@@ -351,50 +342,25 @@ void V8Initializer::LoadV8NativesFromFD(base::PlatformFile natives_pf,
     LOG(FATAL) << "Couldn't verify contents of v8 natives data file";
   }
 #endif  // V8_VERIFY_EXTERNAL_STARTUP_DATA
-  g_opened_files[kNativesFileName] = std::make_pair(natives_pf, natives_region);
+  g_natives_pf = natives_pf;
+  g_natives_region = natives_region;
 }
 
 // static
 base::PlatformFile V8Initializer::GetOpenNativesFileForChildProcesses(
     base::MemoryMappedFile::Region* region_out) {
-  const OpenedFileMap::mapped_type& opened =
-      OpenFileIfNecessary(kNativesFileName);
-  *region_out = opened.second;
-  return opened.first;
+  OpenNativesFileIfNecessary();
+  *region_out = g_natives_region;
+  return g_natives_pf;
 }
 
 // static
 base::PlatformFile V8Initializer::GetOpenSnapshotFileForChildProcesses(
     base::MemoryMappedFile::Region* region_out) {
-  const OpenedFileMap::mapped_type& opened =
-      OpenFileIfNecessary(kSnapshotFileName);
-  *region_out = opened.second;
-  return opened.first;
-}
-
-#if defined(OS_ANDROID)
-// static
-base::PlatformFile V8Initializer::GetOpenNativesFileForChildProcesses(
-    base::MemoryMappedFile::Region* region_out,
-    bool abi_32_bit) {
-  const char* natives_file =
-      abi_32_bit ? kNativesFileName32 : kNativesFileName64;
-  const OpenedFileMap::mapped_type& opened = OpenFileIfNecessary(natives_file);
-  *region_out = opened.second;
-  return opened.first;
-}
-
-// static
-base::PlatformFile V8Initializer::GetOpenSnapshotFileForChildProcesses(
-    base::MemoryMappedFile::Region* region_out,
-    bool abi_32_bit) {
-  const char* snapshot_file =
-      abi_32_bit ? kSnapshotFileName32 : kSnapshotFileName64;
-  const OpenedFileMap::mapped_type& opened = OpenFileIfNecessary(snapshot_file);
-  *region_out = opened.second;
-  return opened.first;
+  OpenSnapshotFileIfNecessary();
+  *region_out = g_snapshot_region;
+  return g_snapshot_pf;
 }
-#endif  // defined(OS_ANDROID)
 #endif  // defined(V8_USE_EXTERNAL_STARTUP_DATA)
 
 // static
@@ -457,20 +423,4 @@ void V8Initializer::GetV8ExternalSnapshotData(const char** natives_data_out,
   }
 }
 
-#if defined(OS_ANDROID)
-// static
-base::FilePath V8Initializer::GetNativesFilePath(bool abi_32_bit) {
-  base::FilePath path;
-  GetV8FilePath(abi_32_bit ? kNativesFileName32 : kNativesFileName64, &path);
-  return path;
-}
-
-// static
-base::FilePath V8Initializer::GetSnapshotFilePath(bool abi_32_bit) {
-  base::FilePath path;
-  GetV8FilePath(abi_32_bit ? kSnapshotFileName32 : kSnapshotFileName64, &path);
-  return path;
-}
-#endif  // defined(OS_ANDROID)
-
 }  // namespace gin
diff --git a/gin/v8_initializer.h b/gin/v8_initializer.h
index 4c03480..dcb5329 100644
--- a/gin/v8_initializer.h
+++ b/gin/v8_initializer.h
@@ -65,19 +65,6 @@ class GIN_EXPORT V8Initializer {
   // Will return -1 if the file does not exist.
   static base::PlatformFile GetOpenSnapshotFileForChildProcesses(
       base::MemoryMappedFile::Region* region_out);
-
-#if defined(OS_ANDROID)
-  static base::PlatformFile GetOpenNativesFileForChildProcesses(
-      base::MemoryMappedFile::Region* region_out,
-      bool abi_32_bit);
-  static base::PlatformFile GetOpenSnapshotFileForChildProcesses(
-      base::MemoryMappedFile::Region* region_out,
-      bool abi_32_bit);
-
-  static base::FilePath GetNativesFilePath(bool abi_32_bit);
-  static base::FilePath GetSnapshotFilePath(bool abi_32_bit);
-#endif
-
 #endif  // V8_USE_EXTERNAL_STARTUP_DATA
 };