Fix Android-specific shmem size code.

In the past, this OS_ANDROID block assigned a value to created_size_
(which appears not to have been used for anything), whereas mapped_size_
used the cross-platform codepath.  In r191098 jschuh@ disabled the
normal assignment of mapped_size_ on Android and made this old code set
the value of mapped_size_.

This Android code block was there to set "bytes" in when Map is called with
a size argument of 0.  So after r191098, mapped_size_ was never set when the
argument was nonzero.  Bring back the mapped_size_ setting and
clean up the Android block.

NOTRY=true
BUG=224646


Review URL: https://chromiumcodereview.appspot.com/13133004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@191250 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 4 insertions, 10 deletions

diff --git a/base/shared_memory_posix.cc b/base/shared_memory_posix.cc
index 607d665..820efa2 100644
--- a/base/shared_memory_posix.cc
+++ b/base/shared_memory_posix.cc
@@ -224,18 +224,14 @@ bool SharedMemory::MapAt(off_t offset, size_t bytes) {
     return false;
 
 #if defined(OS_ANDROID)
+  // On Android, Map can be called with a size and offset of zero to use the
+  // ashmem-determined size.
   if (bytes == 0) {
+    DCHECK_EQ(0, offset);
     int ashmem_bytes = ashmem_get_size_region(mapped_file_);
     if (ashmem_bytes < 0)
       return false;
-
-    DCHECK_GE(static_cast<uint32>(ashmem_bytes), bytes);
-    // The caller wants to determine the map region size from ashmem.
-    bytes = ashmem_bytes - offset;
-    // TODO(port): we set the created size here so that it is available in
-    // transport_dib_android.cc. We should use ashmem_get_size_region()
-    // in transport_dib_android.cc.
-    mapped_size_ = ashmem_bytes;
+    bytes = ashmem_bytes;
   }
 #endif
 
@@ -244,9 +240,7 @@ bool SharedMemory::MapAt(off_t offset, size_t bytes) {
 
   bool mmap_succeeded = memory_ != (void*)-1 && memory_ != NULL;
   if (mmap_succeeded) {
-#if !defined(OS_ANDROID)
     mapped_size_ = bytes;
-#endif
     DCHECK_EQ(0U, reinterpret_cast<uintptr_t>(memory_) &
         (SharedMemory::MAP_MINIMUM_ALIGNMENT - 1));
   } else {