Improve Blob constructor error messages.

LayoutTests/fast/files/blob-constructor-expected.txt

Index: LayoutTests/fast/files/blob-constructor-expected.txt
diff --git a/LayoutTests/fast/files/blob-constructor-expected.txt b/LayoutTests/fast/files/blob-constructor-expected.txt
index 846662652eddab40acf09c014499ddbbe316f40d..d7cf5dc8997b8062b171438b5a31af8c6893fd2f 100644
--- a/LayoutTests/fast/files/blob-constructor-expected.txt
+++ b/LayoutTests/fast/files/blob-constructor-expected.txt
@@ -10,8 +10,8 @@ PASS (new Blob(['hello'], {})) instanceof window.Blob is true
 PASS (new Blob(['hello'], {type:'text/html'})) instanceof window.Blob is true
 PASS (new Blob(['hello'], {type:'text/html', endings:'native'})) instanceof window.Blob is true
 PASS (new Blob(['hello'], {type:'text/html', endings:'transparent'})) instanceof window.Blob is true
-PASS new Blob('hello') threw exception TypeError: First argument of the constructor is not of type Array.
-PASS new Blob(0) threw exception TypeError: First argument of the constructor is not of type Array.
+PASS new Blob('hello') threw exception TypeError: Failed to construct 'Blob': The 1st argument is neither an array, nor does it have indexed properties..
+PASS new Blob(0) threw exception TypeError: Failed to construct 'Blob': The 1st argument is neither an array, nor does it have indexed properties..
 PASS (new Blob([])) instanceof window.Blob is true
 PASS (new Blob(['stringPrimitive'])) instanceof window.Blob is true
 PASS (new Blob([String('stringObject')])) instanceof window.Blob is true
@@ -24,19 +24,19 @@ PASS (new Blob([document])).size is 21
 PASS (new Blob([toStringingObj])).size is 8
 PASS new Blob([throwingObj]) threw exception Error.
 PASS (new Blob([], {unknownKey:'value'})) instanceof window.Blob is true
-PASS new Blob([], {endings:'illegalValue'}) threw exception TypeError: The endings property must be either "transparent" or "native".
+PASS new Blob([], {endings:'illegalValue'}) threw exception TypeError: Failed to construct 'Blob': The 2nd argument's "endings" property must be either "transparent" or "native"..
 PASS new Blob([], {endings:throwingObj}) threw exception Error.
 PASS new Blob([], {type:throwingObj}) threw exception Error.
-PASS new Blob([], {type:'helloî'}) threw exception SyntaxError: type must consist of ASCII characters.
+PASS new Blob([], {type:'helloî'}) threw exception SyntaxError: Failed to construct 'Blob': The 2nd argument's "type" property must consist of ASCII characters..
 PASS new Blob([], {endings:throwingObj1, type:throwingObj2}) threw exception Error 1.
 PASS new Blob([], {type:throwingObj2, endings:throwingObj1}) threw exception Error 1.
-PASS new Blob([], {type:throwingObj2, endings:'illegal'}) threw exception TypeError: The endings property must be either "transparent" or "native".
-PASS (new Blob([], null)) instanceof window.Blob threw exception TypeError: Second argument of the constructor is not of type Object.
-PASS (new Blob([], undefined)) instanceof window.Blob threw exception TypeError: Second argument of the constructor is not of type Object.
-PASS (new Blob([], 123)) instanceof window.Blob threw exception TypeError: Second argument of the constructor is not of type Object.
-PASS (new Blob([], 123.4)) instanceof window.Blob threw exception TypeError: Second argument of the constructor is not of type Object.
-PASS (new Blob([], true)) instanceof window.Blob threw exception TypeError: Second argument of the constructor is not of type Object.
-PASS (new Blob([], 'abc')) instanceof window.Blob threw exception TypeError: Second argument of the constructor is not of type Object.
+PASS new Blob([], {type:throwingObj2, endings:'illegal'}) threw exception TypeError: Failed to construct 'Blob': The 2nd argument's "endings" property must be either "transparent" or "native"..
+PASS (new Blob([], null)) instanceof window.Blob threw exception TypeError: Failed to construct 'Blob': The 2nd argument is not of type Object..
+PASS (new Blob([], undefined)) instanceof window.Blob threw exception TypeError: Failed to construct 'Blob': The 2nd argument is not of type Object..
+PASS (new Blob([], 123)) instanceof window.Blob threw exception TypeError: Failed to construct 'Blob': The 2nd argument is not of type Object..
+PASS (new Blob([], 123.4)) instanceof window.Blob threw exception TypeError: Failed to construct 'Blob': The 2nd argument is not of type Object..
+PASS (new Blob([], true)) instanceof window.Blob threw exception TypeError: Failed to construct 'Blob': The 2nd argument is not of type Object..
+PASS (new Blob([], 'abc')) instanceof window.Blob threw exception TypeError: Failed to construct 'Blob': The 2nd argument is not of type Object..
 PASS (new Blob([], [])) instanceof window.Blob is true
 PASS (new Blob([], /abc/)) instanceof window.Blob is true
 PASS (new Blob([], function () {})) instanceof window.Blob is true
@@ -73,7 +73,7 @@ PASS new Blob({length: 0}).size is 0
 PASS new Blob({length: 1, 0: 'string'}).size is 6
 PASS new Blob({length: 2, 0: new Uint8Array(100), 1: new Int16Array(100)}).size is 300
 PASS new Blob({length: 1, 0: 'string'}, {type: 'text/html'}).type is 'text/html'
-PASS new Blob({length: 0}, {endings:'illegal'}) threw exception TypeError: The endings property must be either "transparent" or "native".
+PASS new Blob({length: 0}, {endings:'illegal'}) threw exception TypeError: Failed to construct 'Blob': The 2nd argument's "endings" property must be either "transparent" or "native"..
 PASS successfullyParsed is true
 
 TEST COMPLETE