Refactor viewport initialization logic out of WebViewImpl.

Source/core/page/PageScaleConstraints.h

Index: Source/core/page/PageScaleConstraints.h
diff --git a/Source/core/html/ime/Composition.h b/Source/core/page/PageScaleConstraints.h
similarity index 71%
copy from Source/core/html/ime/Composition.h
copy to Source/core/page/PageScaleConstraints.h
index 9947d2411a77f4fa0a4cd3dc9758d369a8cfaf7b..92688aadd2aa49de59ef2afc8eff53673454dd2f 100644
--- a/Source/core/html/ime/Composition.h
+++ b/Source/core/page/PageScaleConstraints.h
@@ -28,33 +28,31 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#ifndef Composition_h
-#define Composition_h
+#ifndef PageScaleConstraints_h
+#define PageScaleConstraints_h
 
-#include "wtf/PassRefPtr.h"
-#include "wtf/RefCounted.h"
-#include "wtf/RefPtr.h"
+#include "core/platform/graphics/FloatSize.h"
 
 namespace WebCore {
 
-class Node;
-class Range;
+struct PageScaleConstraints {
+    FloatSize layoutSize;
 
-class Composition : public RefCounted<Composition> {
-public:
-    static PassRefPtr<Composition> create(Node*, Range*);
-    ~Composition();
+    float initialScale;
+    float minimumScale;
+    float maximumScale;
 
-    Node* text() const { return m_text.get(); }
-    Range* caret() const { return m_caret.get(); }
+    PageScaleConstraints();
+    PageScaleConstraints(float initial, float minimum, float maximum);
 
-private:
-    Composition(Node*, Range*);
+    void overrideWith(const PageScaleConstraints& other);
+    float clampToConstraints(float pageScaleFactor) const;
+    void clampAll();
+    void fitToContentsWidth(float contentsWidth, int viewWidthNotIncludingScrollbars);
 
-    RefPtr<Node> m_text;
-    RefPtr<Range> m_caret;
+    bool operator==(const PageScaleConstraints& other) const;
 };
 
 } // namespace WebCore
 
-#endif // Composition_h
+#endif // PageScaleConstraints_h