CdmFileIOImpl: Always SetLength(0) before WriteFile().

media/cdm/ppapi/cdm_file_io_test.cc

Index: media/cdm/ppapi/cdm_file_io_test.cc
diff --git a/media/cdm/ppapi/cdm_file_io_test.cc b/media/cdm/ppapi/cdm_file_io_test.cc
index f171003f6247a3240b2863623fcc4761d9013307..9b4e7dbb65fa36b94dc6e30420a7ced918a27cac 100644
--- a/media/cdm/ppapi/cdm_file_io_test.cc
+++ b/media/cdm/ppapi/cdm_file_io_test.cc
@@ -267,6 +267,36 @@ void FileIOTestRunner::AddTests() {
     CLOSE_FILE
   END_TEST_CASE
 
+  START_TEST_CASE("CloseDuringPendingOverwriteWithLargerData")
+    OPEN_FILE
+    EXPECT_FILE_OPENED(kSuccess)
+    WRITE_FILE(kData, kDataSize)
+    EXPECT_FILE_WRITTEN(kSuccess)
+    WRITE_FILE(kBigData, kBigDataSize)
+    CLOSE_FILE
+    // Make sure the file is empty, not corrupted. See http://crbug.com/410630
+    CREATE_FILE_IO
+    OPEN_FILE
+    EXPECT_FILE_OPENED(kSuccess)
+    READ_FILE
+    EXPECT_FILE_READ(kSuccess, NULL, 0)
+  END_TEST_CASE
+
+  START_TEST_CASE("CloseDuringPendingOverwriteWithSmallerData")
+    OPEN_FILE
+    EXPECT_FILE_OPENED(kSuccess)
+    WRITE_FILE(kBigData, kBigDataSize)
+    EXPECT_FILE_WRITTEN(kSuccess)
+    WRITE_FILE(kData, kDataSize)
+    CLOSE_FILE
+    // Make sure the file is empty, not corrupted. See http://crbug.com/410630
+    CREATE_FILE_IO
+    OPEN_FILE
+    EXPECT_FILE_OPENED(kSuccess)
+    READ_FILE
+    EXPECT_FILE_READ(kSuccess, NULL, 0)
+  END_TEST_CASE
+
   START_TEST_CASE("CloseDuringPendingRead")
     OPEN_FILE
     EXPECT_FILE_OPENED(kSuccess)
@@ -274,6 +304,12 @@ void FileIOTestRunner::AddTests() {
     EXPECT_FILE_WRITTEN(kSuccess)
     READ_FILE
     CLOSE_FILE
+    // Make sure the file is not modified.
+    CREATE_FILE_IO
+    OPEN_FILE
+    EXPECT_FILE_OPENED(kSuccess)
+    READ_FILE
+    EXPECT_FILE_READ(kSuccess, kData, kDataSize)
   END_TEST_CASE
 }