mmap V8 snapshot and ICU data file in the android_webview

This makes it possible to mmap the V8 snapshot and ICU data file
directly from the WebView APK.
Doing so makes it possible to remove the android_webview_telemetry_build
flag which in turns means we can build the WebView with the same
set of flags that Chrome on Android uses.

BUG=442338

Review URL: https://codereview.chromium.org/812393002

Cr-Commit-Position: refs/heads/master@{#310765}

6 files changed, 80 insertions, 25 deletions

diff --git a/base/files/memory_mapped_file.cc b/base/files/memory_mapped_file.cc
index 745a5ff..891fcff 100644
--- a/base/files/memory_mapped_file.cc
+++ b/base/files/memory_mapped_file.cc
@@ -31,6 +31,7 @@ MemoryMappedFile::~MemoryMappedFile() {
   CloseHandles();
 }
 
+#if !defined(OS_NACL)
 bool MemoryMappedFile::Initialize(const FilePath& file_name) {
   if (IsValid())
     return false;
@@ -85,5 +86,6 @@ void MemoryMappedFile::CalculateVMAlignedBoundaries(int64 start,
   *aligned_start = start & ~mask;
   *aligned_size = (size + *offset + mask) & ~mask;
 }
+#endif
 
 }  // namespace base
diff --git a/base/files/memory_mapped_file_posix.cc b/base/files/memory_mapped_file_posix.cc
index ebf38779..168da92 100644
--- a/base/files/memory_mapped_file_posix.cc
+++ b/base/files/memory_mapped_file_posix.cc
@@ -16,6 +16,7 @@ namespace base {
 MemoryMappedFile::MemoryMappedFile() : data_(NULL), length_(0) {
 }
 
+#if !defined(OS_NACL)
 bool MemoryMappedFile::MapFileRegionToMemory(
     const MemoryMappedFile::Region& region) {
   ThreadRestrictions::AssertIOAllowed();
@@ -74,6 +75,7 @@ bool MemoryMappedFile::MapFileRegionToMemory(
   data_ += data_offset;
   return true;
 }
+#endif
 
 void MemoryMappedFile::CloseHandles() {
   ThreadRestrictions::AssertIOAllowed();
diff --git a/base/i18n/icu_util.cc b/base/i18n/icu_util.cc
index e0bd62c..f1fdda7 100644
--- a/base/i18n/icu_util.cc
+++ b/base/i18n/icu_util.cc
@@ -27,21 +27,21 @@
 #define ICU_UTIL_DATA_SHARED 1
 #define ICU_UTIL_DATA_STATIC 2
 
-#if ICU_UTIL_DATA_IMPL == ICU_UTIL_DATA_FILE
+namespace base {
+namespace i18n {
+
 // Use an unversioned file name to simplify a icu version update down the road.
 // No need to change the filename in multiple places (gyp files, windows
 // build pkg configurations, etc). 'l' stands for Little Endian.
-#define ICU_UTIL_DATA_FILE_NAME "icudtl.dat"
-#elif ICU_UTIL_DATA_IMPL == ICU_UTIL_DATA_SHARED
+// This variable is exported through the header file.
+const char kIcuDataFileName[] = "icudtl.dat";
+#if ICU_UTIL_DATA_IMPL == ICU_UTIL_DATA_SHARED
 #define ICU_UTIL_DATA_SYMBOL "icudt" U_ICU_VERSION_SHORT "_dat"
 #if defined(OS_WIN)
 #define ICU_UTIL_DATA_SHARED_MODULE_NAME "icudt.dll"
 #endif
 #endif
 
-namespace base {
-namespace i18n {
-
 namespace {
 
 #if !defined(NDEBUG)
@@ -53,9 +53,10 @@ bool g_check_called_once = true;
 #endif
 }
 
-
 #if defined(OS_ANDROID)
-bool InitializeICUWithFileDescriptor(int data_fd) {
+bool InitializeICUWithFileDescriptor(
+    int data_fd,
+    base::MemoryMappedFile::Region data_region) {
 #if !defined(NDEBUG)
   DCHECK(!g_check_called_once || !g_called_once);
   g_called_once = true;
@@ -67,7 +68,7 @@ bool InitializeICUWithFileDescriptor(int data_fd) {
 #elif (ICU_UTIL_DATA_IMPL == ICU_UTIL_DATA_FILE)
   CR_DEFINE_STATIC_LOCAL(base::MemoryMappedFile, mapped_file, ());
   if (!mapped_file.IsValid()) {
-    if (!mapped_file.Initialize(base::File(data_fd))) {
+    if (!mapped_file.Initialize(base::File(data_fd), data_region)) {
       LOG(ERROR) << "Couldn't mmap icu data file";
       return false;
     }
@@ -135,13 +136,15 @@ bool InitializeICU() {
     bool path_ok = PathService::Get(base::DIR_EXE, &data_path);
 #endif
     DCHECK(path_ok);
-    data_path = data_path.AppendASCII(ICU_UTIL_DATA_FILE_NAME);
+    data_path = data_path.AppendASCII(kIcuDataFileName);
 #else
     // Assume it is in the framework bundle's Resources directory.
+    base::ScopedCFTypeRef<CFStringRef> data_file_name(
+        SysUTF8ToCFStringRef(kIcuDataFileName));
     FilePath data_path =
-      base::mac::PathForFrameworkBundleResource(CFSTR(ICU_UTIL_DATA_FILE_NAME));
+      base::mac::PathForFrameworkBundleResource(data_file_name);
     if (data_path.empty()) {
-      LOG(ERROR) << ICU_UTIL_DATA_FILE_NAME << " not found in bundle";
+      LOG(ERROR) << kIcuDataFileName << " not found in bundle";
       return false;
     }
 #endif  // OS check
diff --git a/base/i18n/icu_util.h b/base/i18n/icu_util.h
index b0a5dbc..5094cb0 100644
--- a/base/i18n/icu_util.h
+++ b/base/i18n/icu_util.h
@@ -5,12 +5,15 @@
 #ifndef BASE_I18N_ICU_UTIL_H_
 #define BASE_I18N_ICU_UTIL_H_
 
-#include "build/build_config.h"
+#include "base/files/memory_mapped_file.h"
 #include "base/i18n/base_i18n_export.h"
+#include "build/build_config.h"
 
 namespace base {
 namespace i18n {
 
+BASE_I18N_EXPORT extern const char kIcuDataFileName[];
+
 // Call this function to load ICU's data tables for the current process.  This
 // function should be called before ICU is used.
 BASE_I18N_EXPORT bool InitializeICU();
@@ -18,7 +21,9 @@ BASE_I18N_EXPORT bool InitializeICU();
 #if defined(OS_ANDROID)
 // Android uses a file descriptor passed by browser process to initialize ICU
 // in render processes.
-BASE_I18N_EXPORT bool InitializeICUWithFileDescriptor(int data_fd);
+BASE_I18N_EXPORT bool InitializeICUWithFileDescriptor(
+    int data_fd,
+    base::MemoryMappedFile::Region data_region);
 #endif
 
 // In a test binary, the call above might occur twice.
diff --git a/base/posix/global_descriptors.cc b/base/posix/global_descriptors.cc
index bcca443..6c18783 100644
--- a/base/posix/global_descriptors.cc
+++ b/base/posix/global_descriptors.cc
@@ -11,6 +11,16 @@
 
 namespace base {
 
+GlobalDescriptors::Descriptor::Descriptor(Key key, int fd)
+    : key(key), fd(fd), region(base::MemoryMappedFile::Region::kWholeFile) {
+}
+
+GlobalDescriptors::Descriptor::Descriptor(Key key,
+                                          int fd,
+                                          base::MemoryMappedFile::Region region)
+    : key(key), fd(fd), region(region) {
+}
+
 // static
 GlobalDescriptors* GlobalDescriptors::GetInstance() {
   typedef Singleton<base::GlobalDescriptors,
@@ -30,23 +40,38 @@ int GlobalDescriptors::Get(Key key) const {
 int GlobalDescriptors::MaybeGet(Key key) const {
   for (Mapping::const_iterator
        i = descriptors_.begin(); i != descriptors_.end(); ++i) {
-    if (i->first == key)
-      return i->second;
+    if (i->key == key)
+      return i->fd;
   }
 
   return -1;
 }
 
 void GlobalDescriptors::Set(Key key, int fd) {
-  for (Mapping::iterator
-       i = descriptors_.begin(); i != descriptors_.end(); ++i) {
-    if (i->first == key) {
-      i->second = fd;
+  Set(key, fd, base::MemoryMappedFile::Region::kWholeFile);
+}
+
+void GlobalDescriptors::Set(Key key,
+                            int fd,
+                            base::MemoryMappedFile::Region region) {
+  for (auto& i : descriptors_) {
+    if (i.key == key) {
+      i.fd = fd;
+      i.region = region;
       return;
     }
   }
 
-  descriptors_.push_back(std::make_pair(key, fd));
+  descriptors_.push_back(Descriptor(key, fd, region));
+}
+
+base::MemoryMappedFile::Region GlobalDescriptors::GetRegion(Key key) const {
+  for (const auto& i : descriptors_) {
+    if (i.key == key)
+      return i.region;
+  }
+  DLOG(FATAL) << "Unknown global descriptor: " << key;
+  return base::MemoryMappedFile::Region::kWholeFile;
 }
 
 void GlobalDescriptors::Reset(const Mapping& mapping) {
diff --git a/base/posix/global_descriptors.h b/base/posix/global_descriptors.h
index 3d7369c31..c774634 100644
--- a/base/posix/global_descriptors.h
+++ b/base/posix/global_descriptors.h
@@ -12,6 +12,7 @@
 
 #include <stdint.h>
 
+#include "base/files/memory_mapped_file.h"
 #include "base/memory/singleton.h"
 
 namespace base {
@@ -36,8 +37,18 @@ namespace base {
 class BASE_EXPORT GlobalDescriptors {
  public:
   typedef uint32_t Key;
-  typedef std::pair<Key, int> KeyFDPair;
-  typedef std::vector<KeyFDPair> Mapping;
+  struct Descriptor {
+    Descriptor(Key key, int fd);
+    Descriptor(Key key, int fd, base::MemoryMappedFile::Region region);
+
+    // Globally unique key.
+    Key key;
+    // Actual FD.
+    int fd;
+    // Optional region, defaults to kWholeFile.
+    base::MemoryMappedFile::Region region;
+  };
+  typedef std::vector<Descriptor> Mapping;
 
   // Often we want a canonical descriptor for a given Key. In this case, we add
   // the following constant to the key value:
@@ -53,12 +64,19 @@ class BASE_EXPORT GlobalDescriptors {
   // Get a descriptor given a key. It is a fatal error if the key is not known.
   int Get(Key key) const;
 
-  // Get a descriptor give a key. Returns -1 on error.
+  // Get a descriptor given a key. Returns -1 on error.
   int MaybeGet(Key key) const;
 
-  // Set the descriptor for the given key.
+  // Get a region given a key. It is a fatal error if the key is not known.
+  base::MemoryMappedFile::Region GetRegion(Key key) const;
+
+  // Set the descriptor for the given |key|. This sets the region associated
+  // with |key| to kWholeFile.
   void Set(Key key, int fd);
 
+  // Set the descriptor and |region| for the given |key|.
+  void Set(Key key, int fd, base::MemoryMappedFile::Region region);
+
   void Reset(const Mapping& mapping);
 
  private: