FileReader: switch to using TypeChecking=Interface

Source/core/fileapi/FileReader.cpp

Index: Source/core/fileapi/FileReader.cpp
diff --git a/Source/core/fileapi/FileReader.cpp b/Source/core/fileapi/FileReader.cpp
index 36361c26914f2c8b0ec7203419fd548a6c00028d..218e28e8a1e5bdb822a3bc4e468269256d8ab944 100644
--- a/Source/core/fileapi/FileReader.cpp
+++ b/Source/core/fileapi/FileReader.cpp
@@ -255,11 +255,7 @@ bool FileReader::hasPendingActivity() const
 
 void FileReader::readAsArrayBuffer(Blob* blob, ExceptionState& exceptionState)
 {
-    if (!blob) {
-        exceptionState.throwTypeError("The argument is not a Blob.");
-        return;
-    }
-
+    ASSERT(blob);
     WTF_LOG(FileAPI, "FileReader: reading as array buffer: %s %s\n", utf8BlobUUID(blob).data(), utf8FilePath(blob).data());
 
     readInternal(blob, FileReaderLoader::ReadAsArrayBuffer, exceptionState);
@@ -267,11 +263,7 @@ void FileReader::readAsArrayBuffer(Blob* blob, ExceptionState& exceptionState)
 
 void FileReader::readAsBinaryString(Blob* blob, ExceptionState& exceptionState)
 {
-    if (!blob) {
-        exceptionState.throwTypeError("The argument is not a Blob.");
-        return;
-    }
-
+    ASSERT(blob);
     WTF_LOG(FileAPI, "FileReader: reading as binary: %s %s\n", utf8BlobUUID(blob).data(), utf8FilePath(blob).data());
 
     readInternal(blob, FileReaderLoader::ReadAsBinaryString, exceptionState);
@@ -279,11 +271,7 @@ void FileReader::readAsBinaryString(Blob* blob, ExceptionState& exceptionState)
 
 void FileReader::readAsText(Blob* blob, const String& encoding, ExceptionState& exceptionState)
 {
-    if (!blob) {
-        exceptionState.throwTypeError("The argument is not a Blob.");
-        return;
-    }
-
+    ASSERT(blob);
     WTF_LOG(FileAPI, "FileReader: reading as text: %s %s\n", utf8BlobUUID(blob).data(), utf8FilePath(blob).data());
 
     m_encoding = encoding;
@@ -297,11 +285,7 @@ void FileReader::readAsText(Blob* blob, ExceptionState& exceptionState)
 
 void FileReader::readAsDataURL(Blob* blob, ExceptionState& exceptionState)
 {
-    if (!blob) {
-        exceptionState.throwTypeError("The argument is not a Blob.");
-        return;
-    }
-
+    ASSERT(blob);
     WTF_LOG(FileAPI, "FileReader: reading as data URL: %s %s\n", utf8BlobUUID(blob).data(), utf8FilePath(blob).data());
 
     readInternal(blob, FileReaderLoader::ReadAsDataURL, exceptionState);