[fsp] Fix flaky tests for aborting read.

chrome/test/data/extensions/api_test/file_system_provider/read_file/test.js

Index: chrome/test/data/extensions/api_test/file_system_provider/read_file/test.js
diff --git a/chrome/test/data/extensions/api_test/file_system_provider/read_file/test.js b/chrome/test/data/extensions/api_test/file_system_provider/read_file/test.js
index 12d5e5a000bc5b4adfa53fa7846f527a8294f55e..00741e77e2ea3478a0da9ef24979d150c2a13d8f 100644
--- a/chrome/test/data/extensions/api_test/file_system_provider/read_file/test.js
+++ b/chrome/test/data/extensions/api_test/file_system_provider/read_file/test.js
@@ -68,13 +68,14 @@ var readBreakpointCallback = null;
  */
 function onReadFileRequested(options, onSuccess, onError) {
   var filePath = test_util.openedFiles[options.openRequestId];
-  if (options.fileSystemId != test_util.FILE_SYSTEM_ID || !filePath) {
-    onError('SECURITY');  // enum ProviderError.
-    return;
-  }
 
-  if (filePath == '/' + TESTING_TIRAMISU_FILE.name) {
-    var continueRead = function() {
+  var continueRead = function() {
+    if (options.fileSystemId != test_util.FILE_SYSTEM_ID || !filePath) {
+      onError('SECURITY');  // enum ProviderError.
+      return;
+    }
+
+    if (filePath == '/' + TESTING_TIRAMISU_FILE.name) {
       var textToSend = TESTING_TEXT.substr(options.offset, options.length);
       var textToSendInChunks = textToSend.split(/(?= )/);
 
@@ -90,26 +91,26 @@ function onReadFileRequested(options, onSuccess, onError) {
 
         reader.readAsArrayBuffer(new Blob([item]));
       });
-    };
+      return;
+    }
 
-    if (readBreakpointCallback)
-      readBreakpointCallback(filePath, continueRead);
-    else
-      continueRead();
-    return;
-  }
+    if (filePath == '/' + TESTING_VANILLA_FOR_ABORT_FILE.name) {
+      // Do nothing. This simulates a very slow read.
+      return;
+    }
 
-  if (filePath == '/' + TESTING_VANILLA_FOR_ABORT_FILE.name) {
-    // Do nothing. This simulates a very slow read.
-    return;
-  }
+    if (filePath == '/' + TESTING_BROKEN_TIRAMISU_FILE.name) {
+      onError('ACCESS_DENIED');  // enum ProviderError.
+      return;
+    }
 
-  if (filePath == '/' + TESTING_BROKEN_TIRAMISU_FILE.name) {
-    onError('ACCESS_DENIED');  // enum ProviderError.
-    return;
-  }
+    onError('INVALID_OPERATION');  // enum ProviderError.
+  };
 
-  onError('INVALID_OPERATION');  // enum ProviderError.
+  if (readBreakpointCallback)
+    readBreakpointCallback(filePath, continueRead);
+  else
+    continueRead();
 }
 
 /**
@@ -304,11 +305,12 @@ function runTests() {
                   chrome.test.assertEq(
                       'AbortError', fileReader.error.name);
                 });
-                fileReader.readAsText(file);
-                setTimeout(chrome.test.callbackPass(function() {
-                  // Abort the operation after it's started.
+                // Set a breakpoint on reading a file, so aborting is invoked
+                // after it's started.
+                readBreakpointCallback = function(filePath, continueCallback) {
                   fileReader.abort();
-                }), 0);
+                };
+                fileReader.readAsText(file);
               }),
               function(error) {
                 chrome.test.fail(error.name);