[SVG] Fix SVGPathBuilder subpath point tracking

http://crrev.com/1623073003 introduced a bug where moveTos only update
the subpath point when immediately following a closePath.

This is incorrect: moveTos should always update the subpath point.

BUG=581451
R=fs@opera.com,pdr@chromium.org

Review URL: https://codereview.chromium.org/1635323002

Cr-Commit-Position: refs/heads/master@{#371783}

third_party/WebKit/LayoutTests/svg/custom/path-multiple-movetos-expected.svg

+<?xml version="1.0" encoding="UTF-8"?>
+<svg xmlns="http://www.w3.org/2000/svg">
+  <rect x="100" y="100" width="100" height="100" fill="green"/>
+</svg>
+

third_party/WebKit/LayoutTests/svg/custom/path-multiple-movetos.svg

+<?xml version="1.0" encoding="UTF-8"?>
+<svg xmlns="http://www.w3.org/2000/svg">
+
+  <rect x="100" y="100" width="100" height="100" fill="red"/>
+
+  <path fill="green" d="
+    m 100 100
+    l 50 0
+    l 0 100
+    l -50 0
+    l 0 -100
+    m 50 0
+    z
+
+    l 50 0
+    l 0 100
+    l -50 0
+    z"/>
+
+</svg>
+

third_party/WebKit/Source/core/svg/SVGPathBuilder.cpp

@@ -56,12 +56,7 @@ void SVGPathBuilder::emitMoveTo(const FloatPoint& p)
 {
     m_path.moveTo(p);
 
-    // If a "closepath" is followed immediately by a "moveto", then
-    // the "moveto" identifies the start point of the next subpath.
-    // [https://www.w3.org/TR/SVG/paths.html#PathDataClosePathCommand]
-    if (m_lastCommand == PathSegClosePath)
-        m_subpathPoint = p;
-
+    m_subpathPoint = p;
     m_currentPoint = p;
 }
 

third_party/WebKit/Source/core/svg/SVGPathBuilder.h

@@ -37,8 +37,7 @@ class SVGPathBuilder final : public SVGPathConsumer {
 public:
     SVGPathBuilder(Path& path)
         : m_path(path)
-        // Starting in ClosePath state ensures correct handling of the first moveTo.
-        , m_lastCommand(PathSegClosePath)
+        , m_lastCommand(PathSegUnknown)
     { }
 
 private: