[SVG] Transform animation leaves traces of text behind.

AffineTransform.inverse() unexpectedly returned an identity matrix when
the matrix was not invertible. This caused invalid rendering for e.g
scale(0) matrices in svg.

BUG=352603

Review URL: https://codereview.chromium.org/200053005

git-svn-id: svn://svn.chromium.org/blink/trunk@169666 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/LayoutTests/svg/text/non-invertible-matrix-text-expected.svg

+<svg width="620" height="450" viewBox="0 0 800 600" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
+	<g id="textGroup" transform="translate(70,300)" font-family="sans-serif" font-size="60" text-rendering="geometricPrecision">
+		<rect x="254" width="1" height="1"/>
+    </g>	
+</svg>

third_party/WebKit/LayoutTests/svg/text/non-invertible-matrix-text.svg

+<svg width="620" height="450" viewBox="0 0 800 600" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" onload="runTest()">
+	<desc>
+		This test places a text element so that it spans across two render tiles (note: the tile width is ~255px at the time of writing this).
+		If the text doesn't span across tiles then other screen updates will "cover up" the bug.
+
+		The scale(0,1) transform matrix has a 0 determinant, which means it cannot be inverted.
+		Any text/shape in svg that has a scale(0) transform means it should be invisible.
+	</desc>
+	<script>
+	<![CDATA[
+		function runTest() {
+			document.getElementById('first').setAttribute("transform", "translate(241.0859375, -21)scale(0, 1)translate(-241.0859375, 21)");
+			document.getElementById('second').setAttribute("transform", "translate(241.0859375, -21)scale(0, 1)translate(-241.0859375, 21)");
+		}
+	]]>
+	</script>
+
+	<g id="textGroup" transform="translate(70,300)" font-family="sans-serif" font-size="60" text-rendering="geometricPrecision">
+		<rect x="254" width="1" height="1"/>
+		<text id="first" x="197.7978515625" y="0" fill="red">s</text>
+		<text id="second" x="229.0576171875" y="0" fill="red">!</text>
+    </g>
+</svg>

third_party/WebKit/Source/core/rendering/PaintInfo.h

@@ -95,7 +95,10 @@ struct PaintInfo {
         if (rect == infiniteRect())
             return;
 
-        rect = localToAncestorTransform.inverse().mapRect(rect);
+        if (localToAncestorTransform.isInvertible())
+            rect = localToAncestorTransform.inverse().mapRect(rect);
+        else
+            rect.setSize(IntSize(0, 0));
     }
 
     static IntRect infiniteRect() { return IntRect(LayoutRect::infiniteRect()); }